Mona Kessel On detail at NASA GSFC missions and observables past, present, and future Measuring Magnetospheric variability Ground-based Space-based

Early Space Exploration Sputnik, October 1957 Explorer 1, January 1958 – First Discovery of the Space Age: Earth’s radiation belts Explorer 2, 3, 4. Pioneer 1, 2, 3,.. Exploration of the 1960’s ATS 1-6 testing concepts in spacecraft design, propulsion, and stabilization, communication systems Discoverer 17 USAF photographic surveillance satellite assessing Soviet capabilities Pioneer 6, 7, 8, 9 Solar wind and magnetic field mapping in interplanetary space Cosmic ray measurements and solar particle studies COSMOS 2-261, Electron 1-4, Soviet satellites to study radiation belts, ionosphere, aurora Explorer 5-35, study trapped radiation, ion and electron density & temperature, solar x-ray Explorer 15, study artificial radiation belt produced by Starfish high-altitude nuclear burst July 1962

Van Allen’s plot of Explorer 3 data in a hotel room on April 3, 1958 Explorer spacecraft made possible early studies of the radiation belts

Space Exploration 1970’s & 1980’s 1973 IMP-8 measured magnetic fields, plasmas, energetic charged particles (e.g., cosmic rays) of Earth's magnetotail and magnetosheath and of the near-Earth solar wind. IMP operated 33 years in its 35 Earth Radii, 12-day orbit GOES series of satellites measuring magnetic fields and particles in geosynchronous orbit, latest one in operation today ISEE 1,2 investigate outermost boundaries of the Earth's magnetosphere, examine structure of solar wind near Earth and shock wave upstream, investigate cosmic rays and solar flare effects ISEE 3 daughter of ISEE 1 with same goals as ISEE 1,2 (1982 ICE) investigate magnetotail and conduct comet encounter 1981 DE investigated coupling between hot, tenuous, convecting plasmas of the magnetosphere and the cooler, denser plasmas and gases corotating in the earth's ionosphere, upper atmosphere, and plasmasphere AMPTE CCE/UKS/IRM studied the access of solar-wind ions to the magnetosphere with lithium and barium tracer ions, 3 satellites to help distinguish between spatial structure and temporal changes. 1970’s Pioneer 10, 11, Voyager 1, 2 to Jupiter, Saturn and beyond. IMP-8 ISEE-3 Voyager-1 For more information go to

Earth SUN Bow Shock IMP-8 spacecraft orbited around the Earth measuring fields and particles Magnetopause Start Finish Magnetic field magnitude Bulk ion speed Bulk ion density B V N August 1985 Bow Shock Magnetopause Day 221 = Aug 9 No particles? IMP-8 made possible early studies around the magnetosphere

Low Energy Proton and Electron Differential Energy Analyzer (LEPEDEA) Spectrograms 16 energy intervals between 5 eV and 50 keV. They had an angular field of view of 9° x 25°

Current Era Space Exploration Geotail CRRES Geotail IMAGE Cluster THEMIS TWINS RBSP MMS

What are the magnetospheric obervables? Magnetic Field Electric Field Ions Electrons Neutrals Background/guidi ng fields; Waves - broad frequency range Bulk parameters: density, speed, temperature; Counts/flux across broad energy range Photons Visible, UV, EUV, FUV Space-based Ground-based Magnetic Field Background field Low frequency waves Photons All Sky images Radars Ionospheric convection

from Russell, C., “The Magnetosphere,” in The Solar Wind and the Earth, eds. S. -I. Akasofu, Y. Kamide, pp , Terra Scientific Publishing Company, Tokyo, 1987.) The basic features of the Earth’s magnetosphere X Z & Radiation Belts & Ring Current

from Russell, C., “The Magnetosphere,” in The Solar Wind and the Earth, eds. S. -I. Akasofu, Y. Kamide, pp , Terra Scientific Publishing Company, Tokyo, 1987.) The basic features of the Earth’s magnetosphere X Z & Radiation Belts & Ring Current

Cluster spacecraft made possible studies of the solar wind and bow shock. Earth’s quasi-perpendicular shock is very thin. & Radiation Belts 1 1 Cluster satellites X Z Proton Density Proton Speed (V X ) Proton Speed (V y ) Proton Speed (V z ) Magnetic Field Electron Density & Radiation Belts & Ring Current

1 1 1b X Y Artists’s conception of Earth’s bow shock

1b Cluster satellites X Z Proton Density Proton Speed (V X ) Proton Speed (V y ) Proton Speed (V z ) Magnetic Field Electron Density Earth’s quasi-parallel shock is thick and turbulent. Cluster spacecraft made possible studies of the solar wind and bow shock. & Radiation Belts & Ring Current

2 2 ISEE made possible the study of the internal structure of the magnetopause. Earth’s magnetopause is thick and multi-layered & Radiation Belts & Ring Current Courtesy J. Dorelli

3 3 X Z Earth’s aurora is a window into MI coupling Polar’s view of auroral oval marks the boundary between open and closed field lines. & Radiation Belts & Ring Current

4 4 X Z Earth’s magnetotail stores and releases energy. & Radiation Belts & Ring Current IMP-8 spacecraft made possible studies of the magnetotail.

5 5 X Z Earth’s radiation belt populations are energy dependent. Van Allen Probes makes possible detailed study of the radiation belts. & Radiation Belts & Ring Current

5 5 X Z Earth’s ring current is not a ring during storms. IMAGE HENA made possible detailed study of the ring current. & Radiation Belts & Ring Current Courtesy Liemohn, LWS SS

5 5 X Z Earth’s inner magnetosphere makes a lot of waves. Van Allen Probes makes possible detailed study of the inner magnetosphere. & Radiation Belts & Ring Current

6 6 X Z Earth’s plasmasphere made visible with EUV IMAGE spacecraft made observations from outside looking in at the plasmasphere. Model courtesy of J. Goldstein & Radiation Belts & Ring Current

Sum up some basic knowledge 1.The bow shock slows, deflects, heat solar wind plasma 2.The magnetopause is a barrier between solar magnetic field and particles and magnetospheric fields and particles. It can be opened during reconnection; stay tuned! 3.The aurora gives us a window (through the filter of MI coupling) into global magnetospheric dynamics and plasma regimes. 4.The magnetotail stores and then explosively releases energy and low energy particles 5.The inner magnetosphere is home to 3 populations of particles that ebb and flow based on sources and losses 6.Outside looking in can reveal large scale structure and dynamics

Magnetospheric variability is dependent on Solar (Wind) Variability 1.Interplanetary magnetic field (IMF) direction 2.Solar wind dynamic pressure (P d ) What about variability?

Courtesy Kozyra, LWS Summer School Northward IMF: Produces cold dense plasma sheets which can be delivered into the inner magnetosphere if the IMF turns southward Southward IMF: Drives strong magnetic activity Magnetopause – IMF direction - reconnection

Courtesy Dorelli, LWS Summer School Magnetopause – IMF direction - reconnection High geomagnetic activity (magnetospheric storms and substorms) Low geomagnetic activity (fewer storms and substorms) “Magnetopause phenomena are more complicated as a result of merging. This is why I no longer work on the magnetopause.” --J. W. Dungey Spacecraft Observations are frequently interpreted in the context of the 2D Dungey cartoon

Measurements of magnetopause reconnection Measure the “effects” of reconnection, e.g., flow. Magnetopause – IMF direction - reconnection Kessel et al., 1996 First observations of Reconnection effects under northward IMF Hawkeye spacecraft made possible the study of reconnection with N IMF.

Magnetopause – IMF direction - reconnection Phan et al., 2003 Cluster and IMAGE spacecraft made possible the study of reconnection. DeHoffman- Teller analysis Wal’en relation Need evidence that the magnetopause is a rotational discontinuity: deHoffman-Teller analysis Wal’en relation

Aurora – window into global magnetospheric dynamics Courtesy Donovan, LWS Summer School It often makes sense to use ground-bases auroral (ionospheric) observations to remote sense magnetospheric dynamics Alaska – Canada – Greenland – Scandanavia - Russia

Courtesy Donovan, LWS Summer School Aurora – window into global magnetospheric dynamics

Aurora Courtesy Donovan, LWS Summer School Aurora – window into global magnetospheric dynamics Ground-based magnetometer chains can show global oscillations, e.g., ULF waves.

4 4 X Z & Radiation Belts & Ring Current Magnetotail – stores and then explosively releases energy

Nagai et al., 1998a At 1107 UT on March 30, 1995, Geotail observed fast tailward flows at a speed of >600 km/s in the magnetotail at a radial distance of 15.5 R E. Tailward convection carrying southward magnetic fields was seen near the neutral sheet. Geotail spacecraft made possible studies of the magnetotail. Geotail observations of a fast tailward flow at X GSM = -15 R E Magnetotail – stores and then explosively releases energy

4 4 X Y Nagai et al., 1998b Geotail spacecraft made possible studies of magnetotail reconnection. Magnetotail – stores and then explosively releases energy Geotail made the seminal observations of reconnection in the 23 R E region

Tailward probe ~ 11 RE Inner probe ~ 9 RE Dubyagin et al., 2011 Entropy Beginning of B perturbation Dipolarization front Flow bursts Reconnection and inner magnetosphere are linked by short-lived flow bursts THEMIS spacecraft made possible studies of the magnetotail. Magnetotail – stores and then explosively releases energy Flow bursts penetrate into the inner magnetosphere

Kozyra, LWS Summer School 2010 ~ Simultaneous double high-latitude reconnection results in large mass transfer from the solar wind into the closed field line region of the magnetosphere. Strong long-lived dawn-dusk electric fields associated with the passage of strong southward IMF by the Earth are the primary cause of magnetic storms. Energy is transferred to the magnetosphere via magnetic reconnection. Convects plasma deep into the inner magnetosphere. Along the way it is adiabatically and non-adiabatically energized to form the stormtime ring current. Solar wind dynamic pressure enhances the geo-effectiveness. Overwhelmingly, emphasis so far has been on the IMF direction as a driver of magnetospheric activity. But solar wind dynamic pressure also has a role. Recap – Magnetopause – Aurora – Magnetotail

Sudden solar wind pressure increase causes inward motion of magnetopause and subsequent loss of high energy electrons. Turner et al., 2014b P dyn BzBz L * max r MP B z also southward Inner magnetosphere – ebbs and flows based on sources and losses

ULF waves were correlated with the structure of the precipitation. An azimuthal electric field impulse generated by magnetopause compression caused inward electron transport and minimal loss. Chorus waves were responsible for most of the precipitation observed outside the plasmapause. Chorus is excited following injection of 1-30 keV plasma sheet electrons into the inner magnetosphere during geomagnetically disturbed times. [Li et al., 2010] Could chorus be excited by temperature anisotropy like EMIC? BARREL Halford et al., 2015 chorus EyEy RBSPICE B - 50 keV A - 50 keV GOES Inner magnetosphere – ebbs and flows based on sources and losses

350 keV 1 MeV 3.5 MeV Role of seed population and chorus waves Boyd, Spence et al., 2014

350 keV 1 MeV 3.5 MeV Role of seed population and chorus waves Boyd, Spence et al., 2014 Source > L* 5.5 GOES sees substorm injection

350 keV 1 MeV 3.5 MeV Role of seed population and chorus waves Boyd, Spence et al., 2014 radial diffusion enhancement

350 keV 1 MeV 3.5 MeV Role of seed population and chorus waves Boyd, Spence et al., 2014 Loss process radial diffusion enhancement

350 keV 1 MeV 3.5 MeV Role of seed population and chorus waves Boyd, Spence et al., 2014 Local Acceleration by chorus GOES sees substorm injection

350 keV 1 MeV 3.5 MeV Role of seed population and chorus waves Boyd, Spence et al., 2014

What is next? Instruments improving resolution and each time we learn something new (like better optics on a telescope resolve objects farther away) Better time resolution, better energy resolution Miniaturization - the trend to manufacture ever smaller mechanical, optical and electronic products and devices. More use of cubesats and smaller missions. NASA recently launched the Magnetospheric Multiscale (MMS) Mission 4 spacecraft in close formation flight!