1. Source and seed populations for relativistic electrons: Their roles in radiation belt changes A. N. Jaynes1, D. N. Baker1, H. J. Singer2, J. V. Rodriguez3,4 Received 24 MAR 2015 Accepted 18 JUL 2015 Accepted article online 22 JUL 2015 Published online 9 SEP 2015 Journal of Geophysical Research: Space Physics

2. Contents Basic Key Point Basic Key Point Van Allen Probe Van Allen Probe Abstract Abstract Event Overview Event Overview Wave activity Wave activity Conclusion Conclusion Discussion Discussion

3. Basic key point Dst It gives information about the strength of the ring current around Earth caused by solar protons and electrons.(Kyoto) Dst It gives information about the strength of the ring current around Earth caused by solar protons and electrons.(Kyoto)ring currentring current Kp The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm 13 position estimated (Potsdam) Kp The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm 13 position estimated (Potsdam)earth's magnetic fieldintegergeomagnetic stormearth's magnetic fieldintegergeomagnetic storm AE index It was measure of global electrojet activity in the auroral zone. The AE index is now widely used for researches in geomagnetism, aeronomy, and solar-terrestrial physics AE index It was measure of global electrojet activity in the auroral zone. The AE index is now widely used for researches in geomagnetism, aeronomy, and solar-terrestrial physics. Magnetopause The magnetopause is the abrupt boundary between a magnetosphere and the surrounding plasma. For planetary science, the magnetopause is the boundary between the planet’s magnetic field and the solar wind Magnetopause The magnetopause is the abrupt boundary between a magnetosphere and the surrounding plasma. For planetary science, the magnetopause is the boundary between the planet’s magnetic field and the solar wind magnetosphereplasmaplanetary sciencesolar wind magnetosphereplasmaplanetary sciencesolar wind Bx By Bz

4. Basic key point Radiation belt? Radiation belt? A radiation belt is a layer of energetic charged particles that is held in place around a magnetized planet A radiation belt is a layer of energetic charged particles that is held in place around a magnetized planetenergeticcharged particlesenergeticcharged particles Substorm injection? Substorm injection? CME(Coronal Mass Ejection)  Geomagnetic storm  ions into the outer radiation belt CME(Coronal Mass Ejection)  Geomagnetic storm  ions into the outer radiation belt Chorus wave? Chorus wave? 0.1fce~0.8fce frequency wave activity(seed acceleration) 0.1fce~0.8fce frequency wave activity(seed acceleration)

5. Van Allen Probes Van Allen Probes?Van Allen Probes?  Consist of two spacecraft  Orbit: 620 ~ 30,500 km  Inclination: 10°  Period: 9 hr  Observe radiation belt storms with excellent  Observe radiation belt storms with excellent spatial and time resolution spatial and time resolution  Life time: 2 years(Launch July 2012 ~ now)  5 Instruments(EMFISIS, ECT, EFW, RPS, RBSPICE)

6. Abstract

7. Electron Local ‘Heating’ Acceleration ~50% storms high-energy electron flux increase ~50% storms high-energy electron flux increase ~25% storms decrease electron flux ~25% storms decrease electron flux 25% storms remain stable 25% storms remain stable Relativistic electron-solar wind speed relationship is not a simple linear one. Relativistic electron-solar wind speed relationship is not a simple linear one. Seed electron L~4.2 Strong southward turning of the IMF Energy into the Earth’s magnetotail Strong southward turning of the IMF Energy into the Earth’s magnetotail Injected by substorm

8. Event Overview August-September 2014 August-September 2014 GOES-13 electrons GOES-13 electrons 30-50 keV 30-50 keV 50-100 keV 50-100 keV 100-200 keV 100-200 keV >0.8 MeV >0.8 MeV >2.0 MeV >2.0 MeV Solar energetic Particle event occurred Solar energetic Particle event occurred

9. Event Overview Predicted AE Predicted AE Predicted Dst Predicted Dst Solar wind pressure Solar wind pressure Solar wind velocity Solar wind velocity Velocity >700km/s~ remain >500km/s several days Velocity >700km/s~ remain >500km/s several days HILDCAA intervals (high-intensity, long-duration, continuous AE activity) HILDCAA intervals (high-intensity, long-duration, continuous AE activity) Absence of source population electrons(northward IMF) Absence of source population electrons(northward IMF)

10. Event Overview VAP data 25 Aug~04 Oct VAP data 25 Aug~04 Oct HOPE, MagEIS, REPT HOPE, MagEIS, REPT Apogee located 5.5 MLT, local time coverage L=4.0 covering ~1.5-8.5MLT Apogee located 5.5 MLT, local time coverage L=4.0 covering ~1.5-8.5MLT 6 12 0 18 Intense occur

11. Event Overview Pitch angle distribution(12 Sep) Pitch angle distribution(12 Sep) REPT REPT MagEIS MagEIS Quickly build up to prestorm levels Quickly build up to prestorm levels Expect relativistic electron flux increase but strongly depleted Expect relativistic electron flux increase but strongly depleted Magnetopause ‘shadowing’  dropout Magnetopause ‘shadowing’  dropout Particle loss through dayside magnetospheric boundary Particle loss through dayside magnetospheric boundary

12. Wave activity storm 12 Sep by Chorus wave storm 12 Sep by Chorus wave Recovery 21 Sep by Hiss wave Recovery 21 Sep by Hiss wave

13. Wave activity POES(850km, 14.1 orbits per day) data over 30-100keV to infer chorus wave intensity POES(850km, 14.1 orbits per day) data over 30-100keV to infer chorus wave intensity Southward substorm electron injection(02:00 UT on 22) Southward substorm electron injection(02:00 UT on 22) 6 12 0 18

14. Wave activity Pc5 power enhanced during main phase of the 12 Sep storm Pc5 power enhanced during main phase of the 12 Sep storm ULF waves played a direct role in the disappearance of the outer belt 13 Sep ULF waves played a direct role in the disappearance of the outer belt 13 Sep

15. Discussion and Conclusion High solar wind speed leas strong substorm activity High solar wind speed leas strong substorm activity IMF northward during solar wind stream, electron flux level can be quiet low IMF northward during solar wind stream, electron flux level can be quiet low IMF southward most case solar wind stream, produce substorm injection of source and seed electrons IMF southward most case solar wind stream, produce substorm injection of source and seed electrons Without source particle, lower band chorus wave are not produced Without source particle, lower band chorus wave are not produced