Theory Earth's Magnetosphere

Earth, like planets, Sun and even galaxies is surrounded by a large magnetic field. For Earth, this is the so-called magnetosphere. Magnetosphere is a vast comet-tail shaped area beginning at Earth Sun side and extending beyond Earth. It is the space manifestation of Earth's magnetic field, the one which acts upon compass' needle. The Earth's magnetic field is mostly yielded by movements in the core as other factors, like magnetised rocks in the upper lithosphere -- the crust and upper mantle -- and the flow of the ocean, also affect Earth's magnetic field. Magnetism generally, is related to temperature, thus rocks heated to certain temperatures lose their magnetism. Earth's original magnetic field was formed some 4.2 billion years ago likely powered by a magnesium oxide-based mechanism, but was exhausted some 565 million years ago, leading to the formation of the inner core and the creation of the churning of molten metals-based process which creates huge electrical currents and provided for the current magnetic field. Earth's magnetic field is a gigantic dipole magnet axis of which is slightly different from Earth's axis; this difference yields magnetic poles being located at different places than geographical ones. With accuracy a distinction must be made between geomagnetic poles which are antipodal points where the axis of a best-fitting dipole intersects the surface of Earth as the magnetic poles are not antipodal as the line on which they lie does not pass through Earth's center. Earth magnetic lines extend into surrounding space. It was not until in 1961 that the Explorer 10 satellite demonstrated that the magnetosphere was not a sphere conforming to the shape of Earth as it featured a far more complex structure. The magnetic energy seething in the magnetosphere get converted to kinetic energy somehow. Understanding the magnetosphere is particularly important because this is where most space assets, including communications satellites, reside and such satellites are sensitive to severe space weather. Between 2000 and 2015, the Earth's magnetic field weakened by about 3.5 percent over North America as it strengthened by about 2 percent over Asia. The region where the field is at its weakest –the South Atlantic Anomaly– has moved steadily westward and weakened further by about 2 percent. It is thought that accelerations in field strength are related to changes in how liquid iron flows and oscillates in the Earth's outer core. The Earth's magnetosphere is also where the interaction occurs between solar storms and us. Solar storms of energetic particles, accelerated by solar activity, are reaching Earth under half and a hour. Tiny such events exist as they are lost in space early since departing the Sun

A View of Earth's Magnetic Field. illustration site 'Amateur Astronomy'

It is the solar wind which is shaping Earth's magnetosphere: sunwards the solar wind compresses Earth's magnetic field; on the opposite side it shapes it comet-tail. Solar wind is a ions plasma emanating from Sun and carrying with it the latter's magnetic field. Sunwards, solar wind hits magnetosphere at the bow shock. It is the place where Earth's magnetic field abruptly deflects solar particles and magnetic field. This compressed part of the magnetosphere extends to about 6-10 Earth radii from Earth. The bow shock, recent ESA studies show, might be as thin as 11 miles (17 km) instead of 62 (100) as outburst of solar wind can push the bow shock closer to Earth. The encounter between the solar wind and Earth's magnetic field is generating sonic booms! In a groundbreaking study by 2018, astronomers found that the bow shock converts energy from the solar wind into heat stored in electrons and ions which is done because electrons of the solar wind encountering the bow shock, momentarily accelerate to such a high speed that the electron stream becomes unstable and breaks down, which robs the electrons of their high speed and converts the energy into heat. Such a study also is rewriting the current understanding of electron heating, generally. The solar wind is piling up along the outer boundary of our magnetosphere, the magnetopause, about 35,000 miles (21,800 km) out. They are then getting diverted sideways. Neutral solar particles which compose the solar wind are following their path leaving the Sun, following the magnetic field lines out to the Earth's heliosheath. During the crash, electrically neutral hydrogen (ENA) atoms are created as the solar protons are stealing the electron from Earth's exosphere hydrogen atoms in those outermost vestiges of our atmosphere, the exosphere, or 'geocorona'. Our dayside exosphere is so tenuous with only about eight hydrogen atoms per cubic centimeter that the interaction is strong. As far as one gets distant from the magnetopause's centerline fewer of the exosphere's hydrogen atoms are hanging around as the interaction with the solar wind is vanishing. In front of this bow shock, or wave, lies a complex, turbulent system called the foreshock. The magnetic field in the bow shock slows the particles, causing most to be deflected away from Earth, though some are reflected back towards the Sun as the latter form a region of electrons and ions called the foreshock region. Particles in the foreshock region are highly energetic, fast moving electrons and ions, getting their high energies by bouncing back and forth across the bow shock as a new observation in 2016 suggests the particles can also gain energy through electromagnetic activity in the foreshock region itself. Conditions in the foreshock change in response to solar particles streaming in, moving magnetic fields and a host of waves, some fast, some slow, sweeping through the region. A special kind of magnetic pulsations are called short large amplitude magnetic structures (SLAMS) having a single, large peak. SLAMS may provide a improved explanation for what accelerates narrow jets of charged particles ('field aligned ion beams') back out into space, away from Earth. Small turbulences in the area can have profound effects downstream. SLAMS generally attempt to move against the gale of the solar wind but ultimately get pushed back and yielding a new boundary ahead of the bow shock. That perturbs the flow of the wind along the magnetosphere, causing a kind of magnetic mirror and attenuating that flow. High-speed jets of plasma forming in Earth's magnetosphere, on the other hand, which are parcels of solar wind, can penetrate deep inside Earth’s protective magnetic shield and cause strong space weather effects. The upflow of plasma from the high-latitude polar cap and auroral regions appears to affect the magnetosphere’s response to variations in the solar wind

Two polar cusps along magnetosphere axis allow solar wind to reach the upper part of the Earth's atmosphere (cusps are where the million-mile-a-hour flow of the solar wind's solar particles collides with and exchanges charges with atoms in the uppermost region of Earth's atmosphere and neutral gases in interplanetary space). Magnetosphere's comet-tail side extends up to 1,000 Earth radii. The "magnetotail" is the shadow of the Earth somehow, there where no solar wind enters as it is about 800,000 miles long. Some solar particles which somehow managed to reach there form the "plasma sheet". The so-called neutral sheet stays at the middle of it. It is where northern and southern part of the Earth's magnetic field cancel. Plasma sheet is too a coating of sort for magnetosphere's tail. Each side of plasma sheet are found tail lobes which usually feature a cold temperature. Boundary between magnetosphere and interplanetary medium is called the magnetopause. Most of Earth’s magnetic field has a foot point at each of both magnetic poles of our planet, determining a closed magnetic field and creating a barrier against charged particles of the solar wind. A smaller portion of Earth’s magnetic field is open however, connecting to Sun’s magnetic field instead of curving back toward Earth. That open magnetic field gives solar charged particles a path into Earth’s atmosphere, creating the aurora. The boundary between these open and closed regions of Earth’s magnetic field is anything but constant. Due to various causes –such as incoming clouds of solar material– the closed magnetic field lines can realign into open field lines and vice versa, changing the location of the boundary between open and closed magnetic field lines. Interactions of geomagnetic storms with the Earth's magnetosphere may cause unstable patches of excess electrons in the ionosphere but it may also deplete the electrons in some locations. Depletion may be due to that electrons are recombining with positively charged ions until there are no excess electrons, or there could also be redistribution with electrons being displaced and pushed away from the region, not only horizontally but vertically too

A view of Earth's magnetosphere. illustration site 'Amateur Astronomy'

Related to Earth protective shield are too an Earth atmosphere's part and the famous Van Allen belts. Ionosphere is Earth's atmospheric layer populated by charged particles. A part of these particles leaks into the plasmasphere, region of cold near-Earth plasma, which is a spherical zone more directly part of magnetosphere and constituted of cold dense gas. In the case of certain space events, the plasmasphere can send a plume up through space, helping to protect. In plasmasphere are found Van Allen belts. Van Allen belts are tori of charged particles: inner belt is made of high-energy protons resulting from upper atmosphere being knocked by cosmic rays as outer belt is high-energy electrons yielded by cosmic rays and magnetosphere acceleration. The Van Allen Belts were discovered through U.S. first unmanned artificial satellite, the Explorer I and named from American physicist James Van Allen of the University of Iowa. A new, third Van Allen belt was discovered in 2013. It is of a transient kind and a storage ring. Totally, three distinct, long-lasting belt structures may be extant in the area at a given moment, with the emergence of a second empty region in between. The real process is that both original belts can merge, or even separate into three belts occasionally. The transient belt is then annihilated by interplanetery shocks for example. The inner belt, stretching from about 1,000 to 8,000 miles above Earth’s surface, is fairly stable. However, the outer ring, spanning 12,000 to 25,000 miles, can swell up to 100 times its usual size during solar storms. Further complicating matters, the outer belt does not always respond in the same way to solar storms as sometimes it swells and sometimes it shrinks, which is caused when electrons in the outer loop either drop into the atmosphere or escape into space. Electrons lost in the outer belt occurs through a process known as electron microbursts. Since that 1958 discovery, observations of the radiation belts and near Earth space have shown that in response to different kinds of activity on the Sun, energetic particles can appear almost instantaneously around Earth, while in other cases they can be wiped out completely. Electromagnetic waves course through the area too, kicking particles along, pushing them ever faster, or dumping them into the Earth’s atmosphere. The bare bones of how particles and waves interact have been described early. Studies went further more recently with a lot of studies of the varied interactions between the Radiation Belts, the solar wind or the magnetosphere. Specific kinds of electromagnetic waves in space –waves that are differentiated based on such things as their frequencies, whether they interact with ions or electrons, and whether they move along or across the background magnetic fields– for example, have been linked to different effects. Space is not empty, nor is it silent. While technically a vacuum, space nonetheless contains energetic charged particles, governed by magnetic and electric fields. In regions laced with magnetic fields, such as the space environment surrounding our planet, particles are continually tossed to and fro by the motion of various electromagnetic waves known as plasma waves, generating 'noise' which can be heard with appropriate tools. Waves in near-Earth terrestrial space are due to waves, due self to fluctuating electric and magnetic fields plowing through clumps of ions and electrons that compose the plasma, pushing some to accelerated speeds. This interaction controls the balance of highly energetic particles injected and lost from in the near-Earth environment. Such plama waves come into four types, whistler-mode waves (which also occur when lightning strike the ground; once translated they sound like space war shoots), chorus waves (which are whistler waves out of the plasmasphere and created when electrons are pushed towards the night side of Earth, accelerated and their density increased -- which in some cases, may be caused by magnetic reconnection. When these low energy electrons hit the plasma, they interact with particles therein, imparting their energy; they sound have a unique, high rising tone), plasmaspheric hisses (which are whistler-mode waves traveling inside the plasmasphere; they have a typical rumbling sound). Both chorus and hiss waves are key shapers of the near-Earth environment including the Van Allen radiation belts. Typically, there is a slow drizzle of escaping electrons from the Van Allen Belts and falling towards Earth, but occasionally microbursts of particles are scattered out. The whistler mode chorus waves, as created by fluctuating electric and magnetic fields as they efficiently accelerate electrons, play a important role in controlling the loss of energetic electrons out of the radiation belts. Plasmaspheric hiss waves also exist at a lower frequency than usually studied as they are particularly good at cleaning out high-energy particles from the radiation belts. They tend to cluster in different regions around Earth compared to their high-frequency counterparts and they sound like static noise when picked up by radio receivers. Their origin is still badly known as they might form when charged particles are injected into the plasmasphere. Hiss and EMIC (Electromagnetic Ion Cyclotron) waves have been observed during a solar storm that showed particle depletion. The principal cause of the acceleration of particles in the Van Allen Belts has been definitively found in 2018 by data collected by the Van Allen Probes mission: it is a process known as local acceleration, caused by electromagnetic waves called chorus waves as the latter speed up the particles. A alternate -- but lesser -- cause of acceleration is what is termed 'radial diffusion' which often occurs during solar storms, with giant influxes of particles, energy and magnetic fields from the Sun slowly and repeatedly nudging particles closer to Earth, where they gain energy from the magnetic fields they encounter

A view of the areas to miscellaneous waves in the magntosphere. illustration site 'Amateur Astronomy'

The Van Allen belts' particles can be depleted by a thousand-fold in mere hours as such dramatic loss events are called 'drop-outs.' They are related to intense solar events disturb the Earth's environment as the belts are losing high-energy, or ultra-relativistic electrons with near-light speeds. During a drop-out, a certain class of powerful electromagnetic waves in the radiation belts can scatter ultra-relativistic electrons, which stream down along these waves and rain down into the atmosphere. Instabilities at the bow shock drive perturbations in the solar wind particles streaming towards the shock and these perturbations can be correlated with another type of magnetized wave closer to Earth, or ULF (ultra low frequency) waves inside the magnetosphere. ULF waves, in turn, are thought to be important for changes in the radiation belts. A extremely sharp boundary at the inner edge of the outer radiation belt, by 7,200 miles (11500km) of altitude, is blocking 'killer electrons' journeying at light speed from breaking inwards to the Earth as scientists previously thought that such electrons drifted into the upper atmosphere and wiped out by air molecules. Why that abrupt barrier exists is still a puzzle however as that might result from a 'plasmaspheric hiss.' The particles at the outer boundary of the plasmasphere cause particles in the outer radiation belt to scatter and remove those from the belt. The radiation belt electrons however, in their quick motion, do not move towards Earth but in the giant loops of the Van Allen belts. Most energetic electrons only slowly drift towards over months and possibly countered by the scattering of the plasmasphere. In the case of a strong solar event, added solar material make the electrons from the outer belt pushed into the nearly empty slot between both Van Allen belts and moves the outer belt boundary inwards along with the electrons of both belts generally. The magnetosphere actually gets quite a bit of energy from the solar wind, even by seemingly innocuous rotations in the magnetic field. All that various waves in the magnetosphere are what can impart energy to the particles surrounding Earth. At the magnetopause, researchers addressed how seemingly small perturbations in the solar wind can have large effects near Earth. Wave-particle interactions in the solar wind in the turbulent region upstream from the bow shock act as a gate valve, dramatically changing the bow shock orientation and strength directly in front of Earth, an area that depends critically on the magnetic field orientation. The extreme bow shock variations cause undulations throughout the magnetopause, which launch pressure perturbations that may in turn energize particles in the Van Allen radiation belts. A strong inverse correlation exists between chorus waves or bird-like sounds and geomagnetic activity during magnetic storms likely yielding strong particle acceleration as a correlation exists between those and low-energy electrons falling out of the belts. Chorus waves, generally, are crucial into providing energy to electrons in the Van Allen belts. The belts are a very dynamic and changing environment as induced by Sun. Fields and waves of electricity and magnetism guide the charged particles within the belts, with the particles surfing on the waves, losing or gaining large amounts of energy along the way as they enter and leave the region. Intense low frequency electric fields and waves at the edge of the radiation belts can last -sometimes for over five hours during geomagnetic storms. The inner belt, where many satellites must operate part of their orbit, is home to the most hazardous and energized particles, mostly protons. Such energized particles vary with altitude. A persistent stripped pattern in the inner radiation belt surrounding Earth is due to high-energy electrons in relation to the slow rotation of Earth, previously considered incapable of affecting the motion of radiation belt particles. Because of the tilt in Earth's magnetic field axis, the planet's rotation generates an oscillating, weak electric field that permeates through the entire belt leading to a zebra stripes pattern of electrons with different energies. Another belt might be extant too around Earth as microbursts, an intense but short lived phase during which electrons drop out of the radiation belts also exist. Swelling and shrinking in response to solar events and radiation, the Van Allen belts are highly dynamic structures within the magnetosphere. Solar geomagnetic events are pushing electrons from outer regions of the magnetosphere deep inside the belt, and in that process, electrons gain energy. There are multiple ways electrons in the radiation belts can be energized or accelerated: radially, locally or by way of a shock. Electrons are either carried by low-frequency waves towards Earth, or gaining energy from relatively higher frequency waves as the electrons orbit Earth, and during shock acceleration, a strong interplanetary shock compresses the magnetosphere suddenly, creating large electric fields that rapidly energize electrons, respectively. In March 1991 long-lived, energized electrons remained within the radiation belts for multiple years after a solar event. Terrestrial Gamma-ray Flashes (TGFs), a little understood phenomenon first discovered by NASA's Compton Gamma-Ray Observatory in the early 1990s are occurring in Earth's atmosphere Although no one knows why, it appears these flashes of gamma rays that were once thought to occur only far out in space near black holes or other high-energy cosmic phenomena are somehow linked to lightning. It is still badly known whether lightning triggers TGFs or if they trigger lightning. TGFs are common and luminous and occurr high in the atmosphere. 1,100 TGFs that fire up each day somewhere on Earth. They last only a few thousandths of a second, but their gamma rays rank among the highest-energy light that naturally occurs on Earth. TGFs also generate a strong burst of very low frequency radio waves. Much weaker radio bursts occur up to several thousandths of a second before or after a TGF as these signals are interpreted as intracloud lightning strokes related to, but not created by, the gamma-ray flash. Scientists suspect TGFs arise from the strong electric fields near the tops of thunderstorms. Under certain conditions, the field becomes strong enough that it drives a high-speed upward avalanche of electrons, which give off gamma rays when they are deflected by air molecules. Could TGFs be responsible for some of the high-energy particles in the Van Allen radiation belts, which damage satellites? A storm, or a tropical storm, for example intensity, alone is not the key factor to TGFs. The inner radiation belt stays largely stable, but the number of particles in the outer one can swell 100 times or more. Plasma in the belts generally flow along a invisible magnetic field lines, while simultaneously creating more magnetic fields as they move. Some solar storms can even cause both belts to swell so much to merge. Both belts even can shrink. There are two broad theories on how the particles in the belt get energy: from radial transport -particles move perpendicular to the magnetic fields within the belts from areas of low magnetic strength far from Earth to areas of high magnetic strength nearer Earth and particle energies correlate to the strength of the magnetic field, increasing as they move towards Earth- or in situ -electromagnetic waves buffet the particles successively raising their speed and energy. For about how how the particles leave the belts, either particles go down or up, either travelling down magnetic field lines toward Earth into the ionosphere, where they stay part of Earth's magnetic system with the potential to return to the belts at some point. Or they are transported up and out, on a one-way trip to leave the magnetosphere forever and enter interplanetary space. There is a substantial, persistent ring current around the Earth even during non-solar storm times, which is carried by high-energy protons encircling our planet. During geomagnetic storms, the enhancement of the ring current is due to new, low-energy protons entering the near-Earth region. The ring current lies at a distance of approximately 6,200 to 37,000 miles (10,000 to 60,000 km) from Earth, and hypothesized in the early 20th century to explain observed global decreases in the Earth’s surface magnetic field. Such changes of the ground magnetic field are described by what's called the Sym-H index. That index was understood however representing the dynamics of only the low-energy protons, and high-energy ones are telling a other story. The ring current, generally, modifies the magnetic field in near-Earth space, which in turn controls the motion of the radiation belt particles that surround our planet

As, unlike Earth, Moon is not surrounded by a global magnetic field, it was thought that the solar wind crashes into the lunar surface without any warning or 'push back' on the solar wind. Signs of the Moon's presence 'upstream' in the solar wind however, like electron beams and ion fountains up to 6,214 miles (10,000km) high above Moon's day side generate a kind of turbulence in the solar wind ahead of the Moon, causing subtle changes in the solar wind's direction and density. The solar plasma thus rings and wiggles a bit constituting a 'foreshock' ahead of the Moon's like there is one also ahead of the Earth's bow shock. Phenomenons at the Moon's surface are generated by sunlight and the flow of the solar wind as such a electric field can generate electron beams by accelerating electrons blasted from surface material by solar ultraviolet light. Also when ions in the solar wind collide with ancient, 'fossil' magnetic fields in certain areas on the lunar surface, they are reflected back into space in a diffuse, fountain-shaped pattern. Other moons and asteroids in the solar system should have too this turbulent layer over their day sides as well

->A More Dynamic View of The Van Allen Belts!
Since the 1950s, when scientists first began forming a picture of the Van Allen Belts, these rings of energetic particles, our understanding of their shape has largely remained unchanged — a small, steady, inner belt, a largely-empty space known as the slot region, and then the outer belt, which is dominated by electrons and which is the larger and more dynamic of both. More recent studies, in the 2010's, have shown that the shape of the belts is actually quite different depending on what type of electron considered. Electrons at different energy levels are distributed differently in these regions. Rather than the classic picture of the radiation belts — small inner belt, empty slot region and larger outer belt — that reveals that the shape can vary from a single, continuous belt with no slot region, to a larger inner belt with a smaller outer belt, to no inner belt at all. Many of the differences are accounted for by considering electrons at different energy levels separately. The researchers found that the inner belt — the smaller belt in the classic picture of the belts — is much larger than the outer belt when observing electrons with low energies, while the outer belt is larger when observing electrons at higher energies. At the very highest energies, the inner belt structure is missing completely. So, depending on what one focuses on, the radiation belts can appear to have very different structures simultaneously. These structures are further altered by geomagnetic storms. Geomagnetic storms can increase or decrease the number of energetic electrons in the radiation belts temporarily, though the belts return to their normal configuration after a time. At a broad range of energies, there are some consistencies in storm dynamics because the electron response at different energy levels differs in the details, but there is some common behavior. For example, it was found that electrons fade from the slot regions quickly after a geomagnetic storm, but the location of the slot region depends on the energy of the electrons. Often, the outer electron belt expands inwards toward the inner belt during geomagnetic storms, completely filling in the slot region with lower-energy electrons and forming one huge radiation belt. At lower energies, the slot forms further from Earth, producing an inner belt that is bigger than the outer belt. At higher energies, the slot forms closer to Earth, reversing the comparative sizes. Measuring the flux of electrons at lower energies had proved difficult in the past because of the presence of protons in the radiation belt regions closest to Earth, creating a noisy background
Further studies by 2017 have shown that geomagnetic storms make the outer radiation belt pulsate dramatically, growing and shrinking in response to the pressure of the solar particles and magnetic field. Meanwhile, the inner belt maintains a steady position above Earth’s surface as composed of high-energy protons and low-energy electrons. Strong solar storms however can push relativistic electrons deep into the inner belt. While the electrons in the slot region quickly decay, the inner belt electrons can remain for many months. Given the rarity of the storms, on a other hand, scientists now understand the inner belt to typically be with lower levels of radiation. One of the processes that allows energetic electrons to escape the Van Allen Belts and fall into Earth's atmosphere, is when solar magnetic storms form in near-Earth space, creating waves that jiggle Earth’s magnetic field lines and kicking electrons out (which creates the red aurora)

click to a renewed, more dynamic view of the Van Allen Belts

->Strong Events Inside the Van Allen Belts
A fortuitous bounce of activity inside the Van Allen belts during that the new solar satellites STEREO entered there has shown that radio-frequency waves called 'whistlers' in the belts, which are accelerating the electrons found there, up to 99 percent of the speed of light, are doing that in just a tenth of a second, and not spans of minutes or tens of hours like previously thought. Whistlers are also participating into the instability of the outer Van Allen Belts with some of the particles within this belt zoom along at close to light speed. That looks like it works like a two-fold process. One mechanism, the time domain structures, or very short duration pulses of electric field that run parallel to the magnetic fields that thread through the radiation belts, gives the particles an initial boost and then whistlers does the final job to kick them up to such intense speeds. Electrons in the belts are also undergoing acceleration from very low frequency plasma waves or persistent stripe-like structures exist in the inner belt caused by Earth’s rotation

->The Slingshot Effect in the Earth's Magnetosphere Tail
The slingshot effect in the Earth's magnetosphere's tail, which affects the solar plasma managing to reach there due to a reconnection process, make that bubbles of energetic electrons are sent back towards the Earth, as they are emitting in the radio wavelengths! They are activating there electrons in the outer Van Allen belt, and they turn them into 'killer electrons' which are able to disrupt the electronics of satellites orbiting in medium, or geosynchronous orbit, like the GPS satellites. Such bubbles, called, 'chorus waves' -and potentially audible to the human ear- are dissipating and turning into 'hiss waves' as their electrons are bouncing back and forth between the Earth's magnetic poles inside the lower layers of the Van Allen belts. Those names given to the phenomenons are a reminder of how the waves sound one translated into audible sounds. The hiss waves, on the other hand, seem to be able to dissipate the killer electrons occurring inside the belts, down to the upper layers of the Earth's atmosphere included. The dissipating hiss waves might be due too to other mechanisms, like, for example, lightnings or the motion itself of the particles inside the Van Allen belts. The question remains however, as far as the safety of the satellites is concerned, to know how those varied processes do really work

The regions closest to Earth's magnetosphere are highly dynamic, albeit poorly understood regions that channel solar wind energy into the magnetosphere. The terrestrial magnetic field cyclically weakens at the time of the equinoxes. Increased strong solar winds can cause Earth’s magnetosphere to wobble. The slowest, low-energy particles, generally, which are encountered at Earth's magnetosphere, come from the solar wind, while higher energy particles come from storms like coronal mass ejections and flares. Flux ropes are strands of magnetic field bundles that come off the Sun and interact with Earth's magnetosphere, as they appear more frequently during a solar minimum. The outflow of oxygen ions from Earth’s upper atmosphere and into the magnetosphere is physics that influence the latter. Furthermore, the processes that heat and energize oxygen ions in the atmosphere are universal in nature. These oxygen ions come and go in episodic bursts. When they are present, which is not all the time, they have dramatic effects on near-Earth space. Among other things, they can affect the rate at which solar-wind energy is transferred to the magnetosphere, and the rate and details of how this stored energy is released to produce aurora. Magnetosphere is a dynamic medium in connection with solar wind especially with solar eruptions. These may lead to magnetosphere's outer part being punctured magnetotail side, solar wind and magnetic lines enter there and break Earth magnetic lines. Ensuing mixed solar-Earth magnetic lines flow into tail, compressing plasmasheet from both sides. Earth parts of magnetic lines eventually reconnect. Earthside lines violently snap back Earth (this is a so-called "reconnection" process). Two models of magnetic reconnection exist. The first model suggests that magnetic reconnection varies in time, like a faucet being turned on and off, releasing particles in short spurts. The second hypothesize that spacecraft observing reconnection events pass through different of them. Complex electron motions occur in the thin layers of electrical current where reconnection happens, allowing them to gain additional energy and accelerate the reconnection process. A part of the reconnection process comes from that some electrons, having no 'guide field' to confine them, are wiggling back and forth. Reconnection events, these giant magnetic bursts can send particles hurtling at near the speed of light and create oscillations in Earth's magnetic fields. During a reconnection event, electrons shoot away in straight lines from the original event, crossing magnetic boundaries. Once across the boundary, the particles curve back around in response to the new magnetic fields they encounter, making a U-turn. Persistent characteristic crescent shape in the electron distributions suggests that it is the physics of electrons that is at the heart of understanding how magnetic field lines accelerate the particles. When magnetic reconnection happens on the day-side, magnetic field lines from the Sun connect directly to Earth’s magnetic field. Once gotten from within the magnetosphere to the boundary between Earth’s magnetic field and the solar wind, further reconnection events occurs allowing charged particles to escape and float along the interplanetary magnetic field. At the difference of what is expected of particles spiraling along a magnetic line and dissipating any magnetic field along, those implied with reconnection let such fields exist temporarily as they likely play a role into reconnection. Reconnection also occurs -- but on scales much smaller -- in turbulent plasma of the magnetosheath where the solar wind is extremely turbulent. Reconnection events also occur in turbulent regions in front of Earth that were previously expected to be too tumultuous for magnetic reconnection, or in magnetic flux ropes which can form in the wake of previous magnetic reconnection events, and in Kelvin-Helmholtz vortices, a phenomenon similar to when wind yield waves on water. Magnetic reconnection occurs when magnetic fields connect, disconnect, and reconfigure explosively, releasing bursts of energy that can reach the order of billions of megatons of TNT. Reconnection, generally, is the poorman's particle accelerator. On the Earth's nightside, magnetic reconnection occurs symmetrically as on dayside, it is asymmetric. Magnetic lines carry solar wind particles with them; these funnel into polar cusps down to upper atmosphere and yield the famous auroras or Northern Lights through an 'auroral oval.' Magnetic field lines pointing in opposite directions spontaneously break and reconnect with other nearby field lines. During auroras, solar wind pushes the boundary of Earth's magnetic fields -or the magnetopause– from its normal position at about 40,000 miles away from Earth in to about 26,000 miles. Sudden, powerful brightening, and increased dynamism of Northern Lights are called 'substorms', as their mechanism is still ill-known. In any case, they originate into the magnetosphere's tail, from where an increase in the solar particles snaps back into the northern regions of Earth. Magnetic substorms are considered space-weather disturbances that occur intermittently, usually several times per day, and last from one to three hours. Earth substorms are accompanied by a range of phenomena, such as the majestic auroral displays seen in the Arctic and Antarctic skies. Substorms also are associated with hazardous energetic particle events that can wreak havoc with communications and satellites. Solar energetic events generally are creating electrical currents on the ground self, which are termed 'geomagnetically induced currents' or GICs. On the magnetosphere's tail side, on the other hand, generally, a solar plasma bubble is expelled from the magnetosphere. Solar events and auroras may work too directly from magnetosphere Sun's side: solar and terrestrial lines connect yielding so-called "cracks" which are punctures in Earth magnetic shield. Solar wind enters puncture and follows magnetic lines to polar cusps there too yielding Northern Lights. Recent findings showed that cracks may last up to 9 hours. X-points or electron diffusion regions also are places where the magnetic field of Earth connects to the magnetic field of the Sun, creating an uninterrupted path between both. Such portals form via the process of magnetic reconnection as mingling lines of magnetic force from the both Earth and the Sun criss-cross and join. The sudden joining of magnetic fields can propel jets of charged particles from the X-point, creating an 'electron diffusion region.' Such magnetic portals open and close dozens of times each day. They're typically located a few tens of thousands of kilometers from Earth. Most portals are small and short-lived; others are yawning, vast, and sustained. Tons of energetic particles can flow through the openings, heating Earth's upper atmosphere, sparking geomagnetic storms, and igniting bright polar auroras. Magnetic portals are invisible, unstable, and elusive. They open and close without warning. Magnetic portals are creating a uninterrupted path leading from our own planet to the Sun's corona! Technically, a event causing a aurora is called a magnetospheric substorm, during which, magnetic reconnection causes energy to be rapidly released along the magnetic field lines, causing the auroras at the North and South Poles. These speedy electrons gain extra energy from changing magnetic fields far from the origin of the substorm that causes the track changes in particle energy over a large distance, a process known as betatron acceleration. Substorms originate opposite the Sun on Earth's 'night side,' at a point about a third of the distance to the Moon. At this point in space, energy and particles from the solar wind store up over time. This is also a point where the more orderly field lines near Earth -- where they look like two giant ears on either side of the globe, a shape known as a dipole since the lines bow down to touch Earth at the two poles – can distort into long lines and sometimes pull apart and 'reconnect.' During reconnection which mostly occur at distances between 80,000 and 120,000 miles away from Earth on the night side, the stored energy is released in explosions that send particles and so-called 'plasmoids' (bits of the tail) out in all directions at speeds of two million miles per hour, especially down the magnetotail away from Earth. The electrodynamic interaction between Earth’s magnetosphere and ionosphere further, produces an asymmetry, biased toward the premidnight sector, consistent with observed distributions in nightside reconnection, plasmasheet flows and in accompanying ionospheric convection. The primary causal agent is the regulation of the distribution of electrical currents flowing within and between the ionosphere and magnetotail. The reconnection of magnetic field lines converts latent magnetic energy into the thermal and kinetic energy of plasma flows as the ionosphere plays an active role when coupled to the magnetosphere in driving the behavior of the magnetotail. Bubbles of plasma, known as plasmoids, shooting away from these magnetic reconnection sites down the magnetotail away from Earth. Changing magnetic fields can cause electrons to zoom along a corkscrew path by the betatron effect. Indeed, electrons moving toward Earth from a substorm will naturally cross a host of changing magnetic fields as those long, stretched field lines far away from Earth relax back to the more familiar dipole field lines closer to Earth, a process called dipolarization. 'Dipolarization fronts,' or bursts of material and energy that collapse Earth's magnetic field at the beginning of a substorm are blobs of magnetized material, or plasma, with temperatures of one million degrees and speeds of one million miles per hour that race toward Earth injecting hyper fast electrons. Betatron acceleration causes the particles to gain energy and speed much farther away from the initial reconnection site, a small amount of energy coming from the reconnection alone. Betatronic acceleration had been predicted since the early 1980s. On the other hand, major solar events in fall 2003 showed how powerful solar streams may further affect the Earth environment as the plasmasphere was blown out, through the poles, to the magnetopause, as a new radiation belt formed at its place. It lasted more than five weeks before being drained away or absorbed by Earth's atmosphere. The plasma sheet is millions of kilometers long and that tail is held together by Earth's magnetic field. The same magnetic field that holds the tail together also connects it to Earth's polar regions. Because of this connection, watching the dance of Northern Lights can reveal much about what's happening in the plasma tail. Vast curtains of aurora borealis have been seen, from space, colliding and producing spectacular outbursts of light. Such burst are not observable from the Earth as the field of view of the observers are limited. Such events are beginning with a broad curtain of slow-moving auroras and a smaller knot of fast-moving auroras, initially far apart. The slow curtain quietly hangs in place, almost immobile, when the speedy knot rushes in from the North. The auroras collide and an eruption of light ensues. The fast-moving knot is believed to be associated with a stream of relatively lightweight plasma jetting through the tail. The stream gets started in the outer regions of the plasma tail and moves rapidly inward toward Earth. The fast knot of auroras moves in synch with this stream. The broad curtain of auroras is connected to the stationary inner boundary of the plasma tail and fueled by plasma instabilities in there. When the lightweight stream reaches the inner boundary of the plasma tail, there is an eruption of plasma waves and instabilities. This collision of plasma is mirrored by a collision of auroras over the poles. Earth’s upper atmosphere, generally, supplies cooler oxygen ions that course outward along Earth's magnetic field lines. This "ion outflow" occurs continuously, but is especially strong during periods when there is more solar activity. Such activity drives oxygen ions out of our planet’s upper atmosphere, particularly in regions where aurora displays are strong. That can act as a brake, or damper, on incoming energy from the solar wind. Such particles gain enough speed and energy through the ionosphere. Energetic neutral atoms or ENAs are fast moving particles produced during particle collisions between charged and neutral particles. Crucially, they move in a straight line from their point of origin, unmolested by the magnetic fields that would constrain charged particles in their travels. Studies of ENAs also allow to check how the magnetosphere react to solar energetic events. The magnetosphere, for example, may immediately compress under the impact of the charged particles from the solar wind as minutes later, the ring current, a ring of charged particles encircling Earth, begins to trap incoming charged particles. About 15 minutes after impact, such trapped particles gyrate down magnetic field lines into Earth's atmosphere, a process known as 'precipitation.' Precipitation is likely mostly due to substorms which release energy from the magnetotail as the ring current activity is to the solar storm directly. Earth's ring current is a clockwise, equatorial plane, electric current which produces a magnetic field in opposition to the Earth's magnetic field and causing a decrease of it. The ring current is mainly carried by ions, most of that protons as alpha particles are also see in the ring current with a certain percentage too oxygen ions, similar to those in the ionosphere of Earth, though much more energetic. Such charged particles are trapped in the Earth's magnetosphere, as the ring current shields the lower latitudes of Earth from magnetospheric electric fields. It therefore has a large effect on the electrodynamics of geomagnetic storms. During a geomagnetic storm, the number of particles in the ring current will increase and there is a decrease in the effects of geomagnetic field. Huge, 25,000 miles (40 000 km) swirls of plasma along the magnetopause can also allow the solar wind to enter, even when Earth’s magnetic field and the IMF are aligned. These swirls were found at low, equatorial latitudes, where the magnetic fields were most closely aligned, and they are driven by a process known as the Kelvin–Helmholtz (KH) effect, which can occur anywhere in nature when two adjacent flows slip past each other at different speeds as such a effect in the magnetosphere also has been seen at work at a wider range locations and when the IMF is arranged in a number of other configurations. Inside the magnetosphere, the density of the space plasma with its charged particles, is much lower than the plasma outside, which is dominated by the solar wind. When the interplanetary magnetic field (IMF) is oriented westward (dawnward) or eastward (duskward), magnetopause boundary layers at higher latitude become most subject to Kelvin–Helmholtz instabilities. That results into a continuous transport of the solar wind into Earth’s magnetosphere. When the interplanetary magnetic field is westward or eastward, magnetopause boundary layers at higher latitude become most subject to KH instabilities. Varied signs are also heralding a impending strong solar event at Earth, like the Van Allen belts accelerating their rotation rate, or the accumulation of a layer of solar particles within the outermost part of the magnetosphere, with values like 4,000-mile thick. Such indices had been already predicted powerful storms like the Carrington Event of the 1850's and the storm of 1958. When solar wind electrons, generally, collide with atmospheric electrons, they transfer some of their energy, heating the atmospheric electrons. Such a larger heat means the electron populations expand upward along the magnetic field lines, creating a vertical electric field, which in turn pulls up the positively-charged and neutral particles, increasing the atmospheric density in columns rather than horizontal layers

A View of Magnetic Field Lines With Bright Red Colors Showing the Densest Part of the Plasma Sheet as Image by the IBEX Mission. A Portion of the Plasma Sheet, Right, Might be Pinched Away from a Larger Mass and Forced down the Magnetotail, a Other Form of a Plasmoid. picture site 'Amateur Astronomy' based on a picture Southwest Research Institute/IBEX Science Team

The Earth's atmosphere, generally, when hit by solar events, is reciprocating by ejecting radiation as a cooling effect to maintain the Earth's energy balance, which creates the expansion and contraction of the upper atmosphere

->Ion Plumes in the Ionosphere, a By-Product of Geo-Magnetic Storms
The ionosphere, when a coronal mass ejection (CME) strikes the Earth's magnetic field, is the place where 'ion plumes' may linger, scientists recently discovered, with effects on GPS, transmissions, airline navigation and radio communications. Such plumes are ionized air (air with an excess electron density) at high altitudes, moving at speed of 2200 mph -1 km/s- (1400 km/h, 1 km/s), as they might originate at the point where the effect of the CME hit is felt near the magnetic equator, over Africa that is. As such plumes form in the ionosphere, they may leak back too into space

As far as the origins of the Earth's magnetic field are concerned, they are thought to be due to the interaction between the two varieties of Earth's core: a liquid core exists around a solid inner core and both acts like a dynamo. Scientists know of two types of movement that cause different variations in the magnetic field, those resulting from slow convection and measured on the scale of a century, and those resulting from rapid hydromagnetic waves, over just a few years. Due to the fields flows and their variation, Earth's magnetic field is a living system. Its axis e.g. is varying and as a result magnetic poles are drifting: north magnetic pole is drifting from Canada to Siberia. Data about magnetic north pole as such was first recorded back in 1831. From the geologic and fossil records we have from hundreds of past magnetic polarity reversals it seems that no dangers is specifically linked to any magnetic reversal. Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200,000 to 300,000 years. It has now be more than twice that long since the last reversal. A reversal happens over hundreds or thousands of years, and it is not exactly a clean back flip, with multiple poles emerging at odd latitudes throughout the process. As seen in the laboratory, reversals do not occur suddenly but they take a few thousand years to complete. During this evolving phase, the magnetic field does not show its dipole bar magnet classical aspect anymore: its it tangled and complicated instead, magnetic poles may be located anywhere on Earth's surface, and there may be more of them than the usual two, with more auroral ovals, and changing of location at the Earth's surface. Reversals modify our magnetosphere but do not make it disappear however and it still protects Earth. Scientists estimate reversals have happened at least hundreds of times over the past three billion years. Reversals happened more frequently after the time of the dinosaurs as a reversal was more likely to happen only about every one million years at that time. Earth's magnetic field has been monitored to have weakened by 10 per cent since the 19th century. This decline has to be put in perspective however as the field today is about twice as strong as normal. It is thought too that this decline would better be the sign that the magnetic field is at the onset of a so-called "excursion" which sees the field swiftly reverse and back over a period of about 400 years. Several such excursions occurred during last millenia which might be linked to weather change on a global scale. Such changes further might be at the origin of several major civilizations demise, like for Egypt about 3,000 years ago, or the Mayas by year 1000 A.D. through the means of drought and famines. The last time that Earth's poles flipped in a major reversal was about 780,000 years ago, in what scientists call the Brunhes-Matuyama reversal. The fossil record shows no drastic changes in plant or animal life, nor glacial change. As the flow of liquid iron in Earth's core creates electric currents, which in turn create the magnetic field, such flows vary. The magnetic north pole, on a other hand, has been creeping northward – by more than 600 miles (1,100 km) – since the early 19th century. It is moving faster now, actually, as scientists estimate the pole is migrating northward about 40 miles per year, as opposed to about 10 miles per year in the early 20th century. There is no indication at last that it the protective shield constituted by the Earth magnetic field ever disappeared completely. A weaker field would certainly lead to a small increase in solar radiation on Earth – as well as a beautiful display of aurora at lower latitudes- but nothing deadly. Moreover, even with a weakened magnetic field, Earth's thick atmosphere also offers protection against the sun's incoming particles. In case of a real weakness of the magnetosphere, the Earth's upper atmosphere ozone protective layer would be affected as a decline in the magnetosphere or the heliosphere, that protective bubble of our Sun and solar system, generally would mean a colder Earth. When the last reversal of the Earth's magnetic field occurred 780,000 years ago, that was the time of Homo erectus which apparently survived as a species. The move of the magnetic pole seems to be due to that the sismic waves as generated by the interactions between the inner and outer core of the Earth are reaching more quickly the surface through the pole. As the electrons in the Van Allen belts further can affect satellites and humans moving through there, the belts also swell and shrink in response to solar energetic events reaching Earth albeit mechanisms remain badly known. For at least a geomagnetic storm, scientists by early 2012 have determined that when the belts shrink, particles moving near the speed of light escape up and out into interplanetary space and not down toward Earth, respondingly triggering a low-density patch of the belt that first appeared at the outer edges of the belts moving inward. It seems likely that some kind of waves aid and that outward motion. Sometimes solar storms can cause a sudden drop in the radiation belt particles, seemingly emptying the belt in only a few hours. This drop out can last for days

->Themis sees More About the Geomagnetic Substorms and Auroras
The Themis mission, which is dedicated to study auroras, has recently shown that geomagnetic substorms and auroras might well be triggered by 'magnetic ropes' directly connecting the Sun to the upper part of the Earth's magnetosphere, the 'magnetopause', at about 40,000 miles (64,000 km) above Earth. Such direct links seem to occur all time, forming and unraveling in a just some minutes, providing however enough time thus, to a brief but significant conduit between the Sun and the Earth. Another solar trick is that the solar wind sometimes affected with knots of magnetism. When such knots reaches the bow shock of the magnetosphere, an explosion occurs, which boosts the temperature of the solar wind particles by ten-fold up to as high as 10 million degrees. Such so-called 'hot flow anomalies' (HFAs) don't play however a significant role into the geomagnetic storms as they are too infrequent. Van Allen belts electrons, on a other hand, are increasing or decreasing in size like a response to the energetic solar events which are reaching to Earth. Their mechanism however remains ill-known. As far, at least, as geomagnetic storms are concerned, physicists determined, by early 2012, that, when the Van Allen belts are decreasing in size, particles, which moves about light speed, are moving outwards -toward interplanetary space- and not toward the Earth. That further, correlatively, makes that a low density area, which begins to appear about the external boundary of the belts, is moving inwards. It looks likely that some kind of waves is facilitating such that move of particles outwards. Solar stroms, sometimes, may yield a sudden drop of the Van Allen belts particles number as they are able to empty the belt on a duration of some hours only! Such a drop may last during days

->Themis Sees More About the Breaching Events in The Magnetosphere!
The Themis mission has seen in 2008, that some breaches in the external layer of the magnetosphere may reach up to 4,000 miles (6,400 km) thick and last up to one hour. The Themis mission further has seen that the most important breaches in the magnetosphere might well occur when both the Earth's magnetic field and the solar one are of the same polarity, at the opposite of what was believed until now!

->The Plasmasphere, the Major Contributor to the Magnetosphere During Superstorms!
Recent studies in 2008 showed that the protons in the plasmasphere have the most efficient effect unto the magnetosphere state during solar superstorms, with it squashed and pressurized by the solar wind and forming a long tail called the plasmaspheric plume where the protons are further energized by the solar wind. When the particles re-enter the magnetosphere, they are the main contributors to it then