The 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.
All of this recent work helps illuminate the nitty gritty details of how seemingly small changes in a system can lead to large variations in the near-Earth space environment where so many important technologies - including science, weather, GPS and communications satellites all reside. Much of this work was based on data from when all five spacecraft were orbiting Earth. Beginning in the fall of , however, two of the THEMIS spacecraft were moved over the course of nine months to observe the environment around the moon. The THEMIS spacecraft continue to work at their original levels of operation and all the instruments function highly effectively.
With their current positioning and the ability to work in conjunction with other nearby spacecraft, scientists look forward to the stream of data yet to come. While in the past terrestrial and planetary auroras have been largely treated in separate books, Auroral Phenomenology and Magnetospheric Processes: Earth and Other Planets takes a holistic approach, treating the aurora as a fundamental process and discussing the phenomenology, physics, and relationship with the respective planetary magnetospheres in one volume.
While there are some behaviors common in auroras of the different planets, there are also striking differences that test our basic understanding of auroral processes. The objective, upon which this monograph is focused, is to connect our knowledge of auroral morphology to the physical processes in the magnetosphere that power and structure discrete and diffuse auroras. The volume synthesizes five major areas: auroral phenomenology, aurora and ionospheric electrodynamics, discrete auroral acceleration, aurora and magnetospheric dynamics, and comparative planetary aurora.
Covering the recent advances in observations, simulation, and theory, this book will serve a broad community of scientists, including graduate students, studying auroras at Mars, Earth, Saturn, and Jupiter. Many spacecraft missions have probed the outer magnetosphere of Earth in conjunction with ground-based and space-borne imagers, and these have contributed enormously to our understanding of the coupled magnetotail-ionosphere system.
It must also be said that the THEMIS project has given a new boost to the ongoing auroral investigations, and thus it is features prominently in this volume. Citation: Keiling, A. Donovan, F. Bagenal, and T. Karlsson Eds. Congratulations to our colleague Victor Sergeev of St. Petersburg University! The injection of high-energy particles into the inner magnetotail is often considered a reliable sign of a magnetic substorm.
These injections are often thought to be caused by flow bursts, short-lived periods of narrow fast flow streams in the magnetotail. To determine whether an injection occurred with each of the flow bursts, they compared the Geotail records with publicly accessible pre particle injection data from Los Alamos National Laboratory LANL satellites, and turned to LANL scientists who had access to classified LANL satellite observations to confirm whether or not an injection occurred with each of the flow bursts in the THEMIS observations. The authors found that only 23 of the 61 Geotail bursts and 16 of the 44 THEMIS bursts were associated with the injection of high-energy particles into geostationary Earth orbit.
The authors found that for a particle injection to make it to geostationary altitudes, the entropy parameter in the flow burst plasma needed to be comparable to the entropy at geostationary Earth orbit. The authors found that a strong solar wind driving, and high plasma pressure, at geostationary orbit could help drive up geostationary entropy and allow the injection of accelerated flow burst plasma.
X-Y locations of the spacecraft observing the flow bursts for two data sets. Thick curve shows the GEO distance 6. Citation: Sergeev, V. Chernyaev, S. Dubyagin, Y. Miyashita, V. Angelopoulos, P. Boakes, R. Nakamura, and M. Henderson , Energetic particle injections to geostationary orbit: Relationship to flow bursts and magnetospheric state, J. The editors of the journal Geophysical Research Letters have selected Lunjin Chen's recent paper, entitled "Modulation of plasmaspheric hiss intensity by thermal plasma density structure," as both a GRL Editor's Highlight and a feature in the "Research Spotlight" section on the back page of Eos , AGU's weekly newspaper.
Over the past 3 decades the hypothesis that chorus waves- a form of highintensity plasma wave often found in the outer magnetosphere- evolve into plasmaspheric hiss in the plasmasphere has grown in prominence. Plasmaspheric hiss is a form of low-frequency radio wave that is often observed in the regions within the plasmasphere that have high plasma densities. Plasmaspheric hiss is important in that the hiss waves interact with highenergy electrons in Earth's geomagnetic field, carving out a swath between the inner and outer Van Allen radiation belts to form the "slot region," a relative safe zone with minimized radiation hazard.
Though modeled simulations of plasmaspheric hiss formation from chorus waves have been able to reproduce the major properties of observed hiss, they often underestimate hiss intensity by decibels. A representative chorus ray that is guided by a density crest. The magenta line represents the ray path, along which wave normal directions are denoted by the short segments color-coded by the propagation time up to 17 seconds.
The model plasma density is shown in the background in gray scale.
Citation: Chen, L. Thorne, W. Li, J. Bortnik, D. Turner, and V. Angelopoulos , Modulation of plasmaspheric hiss intensity by thermal plasma density structure, Geophys. The editors of the Journal of Geophysical Research - Space Physics have selected Jenni Kissinger's recent paper, entitled "Diversion of plasma due to high pressure in the inner magnetosphere during steady magnetospheric convection," as both a JGR Editor's Highlight and a feature in the "Research Spotlight" section on the back page of Eos , AGU's weekly newspaper.
The onslaught of the solar wind on the Sun-facing side of Earth's magnetic field causes terrestrial magnetic field lines to break through magnetic reconnection. The persistent pressure of the solar wind pulls the field lines and the associated plasma around to the magnetotail on Earth's nightside, where magnetic reconnection occurs once again to form the plasma sheet region.
This uneven distribution creates a pressure gradient that drives nightside plasma back toward the planet. The Earthward transport of this nightside magnetospheric plasma is known to occur in one of two ways: as a magnetic substorm or as steady magnetospheric convection SMC. Substorms include acute inflows that cause plasma to pile up in the inner magnetosphere and have been tied to the onset of aurorae. SMC, on the other hand, has been proposed as a mechanism for rebalancing the plasma gradient established between the day and night sides of Earth's magnetic field.
Kissinger et al. All plots are to the same color scale. Citation: Kissinger, J. McPherron, T. Hsu, and V. Angelopoulos , Diversion of plasma due to high pressure in the inner magnetosphere during steady magnetospheric convection, J. Congratulations to Lunjin Chen for winning the Fred L. Scarf award for the best PhD thesis in AGU's Space Physics and Aeronomy section, recognizing outstanding dissertation research that contributes directly to solar-planetary science. He will be receiving his award at the Fall AGU meeting. This happened thanks to the review paper on substorm research by Victor Sergeev and colleagues which is published in this same issue.
Angelopoulos, and R. Nakamura , Recent advances in understanding substorm dynamics, Geophys. Congratulations to Drew Turner for his Nature Physics publication on: "Explaining sudden losses of outer radiation belt electrons during geomagnetic storms" published on-line on January 29 and making the news around the world! Turner's research explains how electron losses through the magnetopause resolve a long standing mystery of electron drop-outs during storm main phase.
After using the Lagrange orbits as observational outposts for 9 months, the two spacecraft were subsequently staged to enter into stable lunar orbits. The P1 probe entered lunar orbit on June 27th, , and now with its twin P2 orbiting in the opposite direction around the moon, the pair's sensitive instruments will yield the first 3D measurements of the moon's magnetic field to determine its regional influence on solar wind particles. The orbit is shown in a fixed Earth-Moon frame horizontal axis, Earth to the left , viewed from above the ecliptic.
Tickmarks are one-day intervals. P2 is leaving its prior trajectory, hovering in the Lagrange point between Earth and Moon centered at L1 in the figure to now enter a stable lunar orbit, its final destination. The P2 thrusters will be fired during three concecutive intervals lasting about 3 hrs at the time of the lunar orbit insertion LOI , indicated by the red trace.
June 27, :. This was a great team effort so far, and our special thanks go out to the JPL and GSFC navigation and flight dynamics teams, as well as to all who helped us with networks support, in particular the DSN team. We could not have accomplished this without you! March 11, :. This photo of the aurora was taken at the Poker Flat Research Range by James Spann during the conference week, featured on Spaceweather. I am afraid now that I have been ruined for life since my first personal viewing of the aurora was so amazing.
Witnessing the connectivity first-hand was particularly special to me. Keynote speaker: Syun Akasofu. Attendee, Nataly Ozak, received a certificate during the banquet for seeing the aurora for the first time. She was one of more than 20 attendees, young and old, who had not seen the aurora without an instrument before coming to this Chapman conference. In the end, everybody who attended saw the aurora!
October 22, :. Article in Der Spiegel on the recent THEMIS findings in German, click here for full article triggering space physics images in popular media, such as the aurora borealis over Iceland's Eyjafjallajokull also see image below. Aurora erupting over the active Iceland volcano Eyjafjallajokull in May February 26, :. At such large distances significant data recovery is impractical, so any data recovered on a best effort basis is primarily for the sake of checking health and status.
This completes the period of ORMs successfully. Significant data recovery will commence again when the probes arrive at lunar distances starting in the fall, followed by capture into the Lissajous orbits. Hats off to the operations and mission design personnel for bringing the probes safely to this point! January 5, :. December 17, :. It begins 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. See full story at: www. A fast-moving knot of auroras is poised to collide with a slower moving curtain hanging over the Arctic. November 19, :. The objective of the review was to demonstrate achievement of the prime mission science objectives, adherence to the mission Level-1 requirements, and report on overall mission technical performance.
It gave us the opportunity to showcase the excellent science accomplishments and superb performance of the instruments and mission. Congratulations to the team for such an exemplary performance. September 22, :. We realize that it takes a great deal of dedication by all involved to make such an accomplishment.
We look forward to continued success of the mission as it enters its extended phase. July 20, :. View larger figure. Image credit: A. Keiling et al. Furthermore, P1 has gone through the longest shadow any of the probes will ever encounter. It was a 4-hour shadow above the 3-hr design limit that resulted in no loss of data other than the precautionary turn-off of the High Voltage power supply for the ESA instrument. All probes are undergoing smaller eclipses you can spot them in the overview plots from the rotation of the magnetic field due to spacecraft moment of inertia changes and lack of sun pulse information.
The essence of the comments of the review board was that the ARTEMIS team has done an outstanding job, especially considering the little 8 months time that has passed since the Senior Review go-ahead. Of course, it was recognized that there is still a lot of work ahead, but the team yesterday presented a reasonable, viable plan, which conveys confidence they can deliver. Even though this is a challenging project, given the resources and time available, this condition was deemed acceptable considering that the THEMIS probes are already operating well and this is an extended-phase mission.
The reviewers have come up with less than a handful of requests for action, which I am certain will strengthen the project, as it moves towards the Orbit Raise Maneuvers in the upcoming summer. Tentatively the ORMs start July 9th. After six months in those orbits, P1 and P2 will be inserted into Lunar orbits where they will make measurements of the Lunar warke, the magnetotail, and the solar wind through September February 11, Asteroid hunters are used to detecting satellites amongst their real quarry, but most satellites move so fast that astronomers can immediately discount them as "obvious" man-made objects.
At apogee, though, THEMIS-B and -C appear to be moving slowly enough so that they can look like a real asteroid until you get enough data to make it clear that they are close in and orbiting Earth. These results are welcome for THEMIS scientists, who can now rest assured that recent reports on tail reconnection have used data collected by actual probes in space. December 16, Earth's magnetic field deflects highly charged particles emitted by the sun, known as solar wind, which speed towards Earth at a million miles per hour.
However, these particles are not fully deflected by the magnetosphere, but instead penetrate through two areas.
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The extent to which these breaches allow solar wind particles to enter through the magnetopshere is dependent on the orientation of the sun's magnetic field. Previously, it was thought that when the sun's magnetic field aligned with that of Earth, the transfer of solar wind particles into Earth's magnetosphere was minimal. However, THEMIS team scientists recently discovered that contrary to longstanding views on how and when solar plasma enters the Earth's magnetosphere, 20 times more solar wind plasma penetrates Earth's magnetosphere when the sun's magnetic field is aligned with that of the Earth.
A similar, though smaller maneuver on TH-C P2 will take place during the early morning hours of Wednesday, October 22nd. We look forward to an exciting second tail season ahead! Our thanks go to Manfred Bester and to the entire mission operations team at UCB for an impeccable execution of a demanding maneuver plan, involving working through some tough hours over the last few days; as well as to the orbit designer Sabine Frey for her careful orbit analysis and optimization. September, They have collected more than hrs of 4 probe dayside conjunctions, and more than hours of 5-probe alignments.
Many of those conjunctions are from the unique vantage point of simultaneous solar wind, foreshocked solar wind, and magnetopause encounters. Owing to the slow dynamic pressure of the solar wind in the last 2 months, most of the inner probe magnetopause encounters are within 3 weeks of August 4th, near the subsolar point.
We expect more flank magnetopause encounters in the 2nd dayside season next summer. THEMIS captured several substorms from a unique vantage point, showing that magnetic reconnection triggered substorm onset. Results appeared in Highlights of Science Express on July 24, and on the cover of the August 15, issue of the magazine.
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Please find the Senior Review report here. The award comes at an important juncture between achieving minimum mission science and ramping up science productivity. Many of those are being presented at the 9th International Conference on Substorms ICS-9 in Graz, Austria, from May , and will form the basis of further studies and presentations during the summer. As of the end of February, THEMIS has observed hours of four- probe conjunctions the requirement was 94 hours , during which it observed 57 substorms.
Of these 57 substorms, about were observed from an excellent vantage point during the period FebFeb So far, the magentotail looks far more interesting than ever before. In total, the EFI had nominal deploys of 20 wire boom and 10 stacer boom systems. This completed the bulk of maneuvers for P1 minor tweak maneuvers to be continued throughout the mission.
More data is expecting to be flowing down soon given this new attitude; software uploads, instrument configurations, and burst triggers are expected to also be finalized in the next 2 months. No anomalies were encountered since the release of the most recent, formal Mission Operations Report No.
All instruments are turned on and are collecting science data. All attitude maneuvers achieved their goals. Post-maneuver processing as well as orbit and attitude determination are in progress to provide the baseline Probe states for the final Mission Design run prior to the first set of orbit maneuvers. All five probes are currently in No anomalies were encountered. Please note that the deployment sequence was optimized and now only requires 14 steps The only remaining step for this probe is the axial boom release step 13 which is scheduled for later this week.
The EFI spin-plane boom deployment went very smooth - there were no issues with dynamic stability during the deployment or following spin-up maneuvers. The dual pulse spin-up procedure worked very well. According to the EFI team, the instrument generates science data with excellent quality. The FPGA was successfully reset on these probes. A work-around is still tested on FlatSat. No other anomalies were encountered.
The observed spin rate change during the deployment was nominal. The EFI Scientist reported nominal sensor operation. Report No. All 20 thruster across the constellation have now been exercised and function nominally. This mode is required to be used for all spin-up maneuvers to maintain dynamic stability of the probes, once EFI spin-plane boom deployment has started. All five probes are safe and healthy, and are in stable orbits. The attitudes are nearly ecliptic normal. All science instruments are operational and are collecting data. The mission orbit placement will begin in late August, and will be completed in preparation of the first winter observing season "Tail 1" when the probe orbits will be aligned with the Earth's magneto tail.
Meanwhile, all five probes are maintained in temporary "coast phase" orbits. Performed perigee raise maneuvers with each probe to control the differential precession of the argument of perigee amongst the five probe orbits and to calibrate the thrusters:. Performed the first of a series of additional orbit maneuvers to position the five probes for the coast phase:. All delta V maneuvers were accomplished in side thrust mode, using the two tangential thrusters with a 60 deg thrust angle at a spin rate of approximately 20 rpm.
Small attitude and spin rate changes were encountered as an undesired, but unavoidable byproduct of the side thrust maneuvers. These changes will be corrected later. Performed post-maneuver operations, including maneuver reconstruction and calibration, orbit and attitude determination. Refined mission trajectory design for the coast phase, based on inputs from the PI and the science team. All pass activities are conducted with FOT on console.
Passes are currently still taken in blind acquisition mode, allowing a high degree of operational flexibility for re-planning. ATS loads are used primarily to reconfigure instruments in various orbit regions and to support maneuver operations. Characterization of instruments in science-like orbits.
A dedicated 'fields' orbit for all five probes will start on DOY The maneuver sequence is designed such that minimum fuel is consumed and virtually all of the perigee and apogee changes count towards the mission orbit placement. The entire sequence alternates between boom deployment steps, instrument test and calibration runs, and data recovery near perigee; this takes 6 orbits 8 days to complete. These two probes require the largest fuel usage for their orbit placement.
Delaying the boom deployment will allow for a rapid ascent of THEMIS B to the P1 orbit by using efficient attitude precession maneuvers and axial thruster burns for the delta V maneuvers. The other three probes will perform their mission orbit placement using the tangential thrusters in "side thrust mode". March 14th, In the past day, we p erformed telecom tests at apogee with all probes and multiple ground stations. These were very successful showing us the probes can telemeter at 64 K bits per second to Berkeley throughout this orbit.
Probe E SST was reconfigured.
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Science data is being collected and returned successfully in Slow Survey mode. That would complete the initial commissioning on all instruments. Each was ramped up successfully to full voltage and all four performed beautifully. We plan to get back to that probe tomorrow. Currents looked good and stable, but the expected packet telemetry was not coming through.
Each was ramped up successfully to full voltage and all five performed perfectly. Probe A and E SSTs were turned on, but due to sun in their apertures at these attitudes, their currents red-limited and they were turned off before the end of their contacts. By the end of the day, all SSTs were powered off in order to allow manevers to proceed.
Probes A, E, D and B were maneuvered to ecliptic normal, enabling better communications, stable power and thermal conditions. Fuel usage since launch has been a mere 0. Science and engineering data for all probes was played out. All probes remain in good health and their orbits are well known. March 7th, Today, all ESA covers were successfully opened using their primary actuators. Later this week we will turn on the High Voltage to the ions and electrons.
We are replanning these maneuvers for later in the week, while proceeding ahead with the commissioning in the current attitude. March 4th, Over the weekend, Probes B and C were maneuvered so that their antennae were north-south with respect to the ecliptic. This was confirmed when the Probe passed through perigee and its FGM data showed the tilt. Probe C's maneuver sequence was modified to include newly determined information about the probes, so C's maneuver on Sunday was picture perfect. All probes continue taking magnetic data in preparation for a maneuver to ecliptic normal attitude.
This allows science data to be recovered in an unusual mixed configuration; ie. Probes D and E had their magnetometer booms deployed. All probes are taking magnetic data in preparation for a maneuver to ecliptic normal attitude at the end of the week. February 24th, The last 24 hours have seen an amazing amount of accomplishments on the five probes.
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We recovered all engineering and science data from all probes, too. As the probes have begun to separate a little, we were also able to contact three probes simultaneously using three different ground stations. Probes E, D and C telemetered to Berkeley, Santiago and Wallops at , and kbps, and the data routing network worked perfectly. Of the 20 passes during the day, Berkeley had 13, Santiago 1, Haartebeestok 1 and Wallops had 5 tracking passes. All five probes remain in excellent health. Temperatures are very mild on the probes now in their nominal attitude with sun on their side panels.
All systems were nominal in current and temperature. All five probes were de-spun from their initial spin rate of RPM down to 11 RPM, in preparation for the upcoming magnetometer boom deployment. This involved firing the radial thrusters for 6 to 7. As we expected, each spacecraft wobbled a bit, but telemetry and commanding were unaffected. Engineers are continuing data collection and analysis on two technical items. The first item involves the occasional false over-voltage trips in charging circuits and the second involves measuring the command and telemetry link performance.
There were no over-voltage-trips today. Communications with the probes have been very successful with Berkeley Ground Station but not yet with Wallops. Last night we had successful telemetry at 64 KHz at a distance of over km using Probe B yet we were unable to lock on RF carrier with Wallops just moments earlier. FGM sensor data recording began and we should see the first science data play out in the next orbit.
Probe A was rolled so that the sun is on its side-panels rather than on its top. This will cool the top down. All five probes are in very good health. Engineers are finalizing data collection and analysis on two technical items at this time. The first item involved the occasional false over-voltage trips in charging circuits and the second involved measuring the command and telemetry link performance. Communications with the probes have improved greatly due to better orbit and attitude information.
For example, last night we had successful telemetry at 64 KHz at a distance of over km using Probe A. Each maneuver took about 2. This attitude provides better temperatures around the probes as well as better communication to the ground. After that time, Probe A will be rolled to the same attitude as the other four. All five probes are in very good health, but the team is currently working two technical items at this time, one regarding occasional false over-voltage trips in charging circuits and the second involves measuring the command and telemetry link performance.
First, the occasional false over-voltage-protection trips are essentially due to the fact that the the batteries are fully charged. Small noise on the battery readings have caused the circuits to occasionally think that the battery is too full. In response, the circuits shunt power for a few minutes until the battery voltage is a fraction lower.
It has become apparent that the solar arrays are putting out more power than projected, and that the shunts are barely able to regulate. Thus, we have turned on additional heaters to balance the energy in the probe. Second, initial poor communications with the probes is to a large extent due to a shorter than predicted orbit. The orbits are now 1. As we have learned how to point the antenna better, communications at high data rates are a regular occurrence.
Still, we've noticed that Charlie and Bravo have the best performance while the other three have dB dips in their signals at certain orientations. All trajectories appeared right on target. First contact at the Berkeley Ground Station was successful. Watch the launch video. Jetty Park is 2. The NASA Associate Administrator for the Science Mission Directorate, Mary Cleave, stated that the mission is a pathfinder for future Heliospheric constellations and thanked the team for its efforts in making it possible for the entire community.
Deputy AA Colleen Hartman stated that this is a scientifically very exciting mission and that she felt really fortunate to see it through end-to-end in her term. Dick Fisher, Heliophysics Division director, stated that the team performance in general and in this review in particular, sets a very high standard for missions to come. Citation: Nishimura, Y. Geophysical Research Letters, Source: Lipuma, L. Eos Research Spotlight: Zastrow, M.
Source: Cook, T. Citation: Gallardo-Lacourt, B. Journal of Geophysical Research: Space Physics, , — Hietala, M. Hartinger, F. Plaschke, V. Angelopoulos Citation: Takahashi, K. Roles of flow braking, plasmaspheric virtual resonances, and ionospheric currents in producing ground Pi2 pulsations. Journal of Geophysical Research: Space Physics, , — Red and blue colors indicate the upward and downward field-aligned current direction. Empirical Modeling of Dayside Magnetic Structures Associated With Polar Cusps This work by Tsyganenko and Andreeva deals with the solar windward side of the Earth's magnetosphere, which is most exposed to the incoming flow of interplanetary plasma, and, as such, takes the first blow during space storms.
Citation: Tsyganenko, N. Empirical modeling of dayside magnetic structures associated with polar cusps. Citation: Archer, M. First results from sonification and exploratory citizen science of magnetospheric ULF waves: Long-lasting decreasing-frequency poloidal field line resonances following geomagnetic storms. Space Weather, Fellow Aurora Chaser Robert Downie kneels in the foreground while photographer Ryan Sault captures the narrow ribbon of white-purple hues overhead.
The vibrant green aurora is seen in the distant north, located to the right in the photo. In this issue, Gallardo-Lacourt et al. Their results demonstrate that STEVE is different than aurora since the observation is characterized by the absence of particle precipitation. Credit: Ryan Sault. Number Lon Lines Total number of longitudinal half-plane cross-sections, equally spaced and starting from the Starting Longitude.
Starting Longitude The magnetic longitude from which the set of longitudinal cross-sections start, measured as increasingly positive toward the east, in the Solar Magnetic SM frame. Field Line Refresh Rate The time period of the frequency at which the magnetic field lines will be recalculated for animation purposes.
Ramp Stop Color corresponding to the highest mapped value. Max Translucency The level of field-line translucency of corresponding to the minimum mapped field strength available when the Color Mode is Latitude Line. Scale Options are: Linear - color ramp based on a linear scale Log - color ramp based on a logarithmic scale Style Sets the style of the field contour line. Width Sets the width of the field contour line. ADS Google Scholar. Dungey, Interplanetary field and the auroral zones, Phys.
Akasofu and Y. Google Scholar. Beynon, R.
Boyd, S. Cowley, and M. Cowley, Plasma populations in a simple open model magnetosphere, Space Sci.