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Cold, keV, & MeV ion signatures of westward moving auroral bulge at L=4 in equatorial plane

Cold, keV, & MeV ion signatures of westward moving auroral bulge at L=4 in equatorial plane. M. Yamauchi 1 , I. Dandouras 2 , P.W. Daly 3 , H. Frey 4 , P.-A. Lindquvist 5 , G. Stenberg 6 , Y. Ebihara 7 , R. Lundin 1 , H. Nilsson 1 , H. Reme 2 , M. Andre 6 , E. Kronberg 3 , and A. Balogh 8

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Cold, keV, & MeV ion signatures of westward moving auroral bulge at L=4 in equatorial plane

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  1. Cold, keV, & MeV ion signatures of westward moving auroral bulge at L=4 in equatorial plane M. Yamauchi1, I. Dandouras2, P.W. Daly3, H. Frey4, P.-A. Lindquvist5, G. Stenberg6, Y. Ebihara7, R. Lundin1, H. Nilsson1, H. Reme2, M. Andre6, E. Kronberg3, and A. Balogh8 (1) IRF, Kiruna, Sweden, (2) CESR, Toulouse, France, (3) MPS, Katlenburg-Lindau, Germany, (4) UCB/SSL, Berkeley, CA, USA, (5) Alfven Lab., KTH, Stockholm, Sweden, (6) IRF, Uppsala, Sweden, (7) IAR, Nagoya U., Nagoya, Japan, (8) Blackett Lab., ICL, London, UK ICS-9, Graz, 2008-5 / revised for IMC-workshop, Espoo, 2008-7

  2. overview 90 min MeV 102 keV Z=0 Re, R=4 Re 0.01~40 keV Cluster perigee (19 MLT, R≈4 RE, Z=0 RE) 25 min H+ O+ H+ He+

  3. What do these events indicate? From 06:43 UT event (a) Composition of cold plasma  plasmasphere-magnetosphere coupling in the inner magnetosphere. (b) Mass-dependent filling of medium-energy ring current ions (and by auroral bulge?)  drift motion (c) Propagation of large DC electric field in the equatorial plane. (d) Inter-SC difference of energetics  non-gyrotropic From 06:48 UT event (not today) (d) Bi-parallel beams in the equatoral plane (e) Equatorial signature of the transpolar arc.

  4. Spacecraft * Near equator (Z ≈ 0 RE) * Perigee (R ≈ 4 RE) S/C * 19 MLT north sun SC1-SC4 ≈ 25 sec SC1-SC3 ≈ 1 min dusk dawn U tail E south

  5. IMAGE/FUV 06:26~06:56 UT S/C 06:26 UT 06:34 UT 06:42 UT 06:50 06:28 UT 06:36 UT 06:44 UT 06:52 06:30 UT 06:38 UT 06:46 UT 06:54 06:32 UT 06:40 UT 06:48 UT 06:56

  6. IMAGE/FUV 06:26~06:56 UT ~06:43 event S/C 06:26 UT 06:34 UT 06:42 UT 06:50 06:28 UT 06:36 UT 06:44 UT 06:52 06:30 UT 06:38 UT 06:46 UT 06:54 06:32 UT 06:40 UT 06:48 UT 06:56

  7. IMAGE/FUV 06:26~06:56 UT ~06:43 event ~06:48 event S/C 06:26 UT 06:34 UT 06:42 UT 06:50 06:28 UT 06:36 UT 06:44 UT 06:52 06:30 UT 06:38 UT 06:46 UT 06:54 06:32 UT 06:40 UT 06:48 UT 06:56

  8. #1 #2 ~06:26 UT: minor substorm ~06:38 UT: new glowing MCQ = Cluster conjugate

  9. Observation of 06:43 UT (#1) event 1. Sudden change in particle flux (> 40 keV, > 10 keV, and < 100 eV) when aurora bulge arrived Cluster’s conjugate ~19 MLT. 2. Change is simultaneous at all SC (SC-3 leading by 1~10 sec). 3. Simultaneous DC field change (tailward E~8mV/m, Pi2-like rarefaction |B|≈|BZ| up to 20%) without special wave activity. 4. Increase in medium energy (~100 keV, mass dependent) ion flux. Diamagnetic effect by ∆PP can quantitatively explain ∆PB. 5. Decrease in energetic e- (>30 keV) and ions (> 0.1 MeV) 6. Temporal (about 1 min) change of pitch-angle of 10-40 keV to more field-aligned than perpendicular. 7. Bulk motion of cold He+ and H+ (no cold O+ or He++). The ion velocity (20km/s, duskward) agrees with the ExB velocity.

  10. overview 90 min MeV 102 keV Z=0 Re, R=4 Re 0.01~40 keV Cluster perigee (19 MLT, R≈4 RE, Z=0 RE) 25 min H+ O+ H+ He+

  11. 06:43 UT 06:43 UT keV ions of ionospheric origin?  //  //  // No mass-energy dispersion Bi-directional = not auroral ions

  12. Observation of 06:43 UT (#1) event 1. Sudden change in particle flux (> 40 keV, > 10 keV, and < 100 eV) when aurora bulge arrived Cluster’s conjugate ~19 MLT. 2. Change is simultaneous at all SC (SC-3 leading by 1~10 sec). 3. Simultaneous DC field change (tailward E~8mV/m, Pi2-like rarefaction |B|≈|BZ| up to 20%) without special wave activity. 4. Increase in medium energy (~100 keV, mass dependent) ion flux. Diamagnetic effect by ∆PP can quantitatively explain ∆PB. 5. Decrease in energetic e- (>30 keV) and ions (> 0.1 MeV) 6. Temporal (about 1 min) change of pitch-angle of 10-40 keV to more field-aligned than perpendicular. 7. Bulk motion of cold He+ and H+ (no cold O+ or He++). The ion velocity (20km/s, duskward) agrees with the ExB velocity.

  13. Sudden change in ion and field 06:43:00 06:48:30

  14. Timing (ion = 12sec resolution) 06:43:00 06:48:30 leading 60s behind 25s behind

  15. Timing (E-field) 3 min

  16. Timing (B-field)

  17. Observation of 06:43 UT (#1) event 1. Sudden change in particle flux (> 40 keV, > 10 keV, and < 100 eV) when aurora bulge arrived Cluster’s conjugate ~19 MLT. 2. Change is simultaneous at all SC (SC-3 leading by 1~10 sec). 3. Simultaneous DC field change (tailward E~8mV/m, Pi2-like rarefaction |B|≈|BZ| up to 20%) without special wave activity. 4. Increase in medium energy (~100 keV, mass dependent) ion flux. Diamagnetic effect by ∆PP can quantitatively explain ∆PB. 5. Decrease in energetic e- (>30 keV) and ions (> 0.1 MeV) 6. Temporal (about 1 min) change of pitch-angle of 10-40 keV to more field-aligned than perpendicular. 7. Bulk motion of cold He+ and H+ (no cold O+ or He++). The ion velocity (20km/s, duskward) agrees with the ExB velocity.

  18. increase in 101~2 keV ion flux decrease in 102~3 keV ion flux H+ < 90 keV H+ > 160 keV

  19. increase in 101~2 keV ion flux He < 350 keV O < 0.9 MeV O > 1.4 MeV He > 700 keV decrease in 102~3 keV ion flux

  20. increase-decrease combination First increase, then decrease

  21. 06:43 UT keV ion increase is NOT mass dependent No mass-energy dispersion (2~10 keV)

  22. Observation of 06:43 UT (#1) event 1. Sudden change in particle flux (> 40 keV, > 10 keV, and < 100 eV) when aurora bulge arrived Cluster’s conjugate ~19 MLT. 2. Change is simultaneous at all SC (SC-3 leading by 1~10 sec). 3. Simultaneous DC field change (tailward E~8mV/m, Pi2-like rarefaction |B|≈|BZ| up to 20%) without special wave activity. 4. Increase in medium energy (~100 keV, mass dependent) ion flux. Diamagnetic effect by ∆PP can quantitatively explain ∆PB. 5. Decrease in energetic e- (>30 keV) and ions (> 0.1 MeV) 6. Temporal (about 1 min) change of pitch-angle of 10-40 keV to more field-aligned than perpendicular. 7. Bulk motion of cold He+ and H+ (no cold O+ or He++). The ion velocity (20km/s, duskward) agrees with the ExB velocity.

  23. Decrease in > 40 keV electron flux e- > 40 keV cf. some decrease in < 30 keV ions

  24. Observation of 06:43 UT (#1) event 1. Sudden change in particle flux (> 40 keV, > 10 keV, and < 100 eV) when aurora bulge arrived Cluster’s conjugate ~19 MLT. 2. Change is simultaneous at all SC (SC-3 leading by 1~10 sec). 3. Simultaneous DC field change (tailward E~8mV/m, Pi2-like rarefaction |B|≈|BZ| up to 20%) without special wave activity. 4. Increase in medium energy (~100 keV, mass dependent) ion flux. Diamagnetic effect by ∆PP can quantitatively explain ∆PB. 5. Decrease in energetic e- (>30 keV) and ions (> 0.1 MeV) 6. Temporal (about 1 min) change of pitch-angle of 10-40 keV to more field-aligned than perpendicular. 7. Bulk motion of cold He+ and H+ (no cold O+ or He++). The ion velocity (20km/s, duskward) agrees with the ExB velocity.

  25. Change in PA distirbution 06:43 06:48:30

  26. Observation of 06:43 UT (#1) event 1. Sudden change in particle flux (> 40 keV, > 10 keV, and < 100 eV) when aurora bulge arrived Cluster’s conjugate ~19 MLT. 2. Change is simultaneous at all SC (SC-3 leading by 1~10 sec). 3. Simultaneous DC field change (tailward E~8mV/m, Pi2-like rarefaction |B|≈|BZ| up to 20%) without special wave activity. 4. Increase in medium energy (~100 keV, mass dependent) ion flux. Diamagnetic effect by ∆PP can quantitatively explain ∆PB. 5. Decrease in energetic e- (>30 keV) and ions (> 0.1 MeV) 6. Temporal (about 1 min) change of pitch-angle of 10-40 keV to more field-aligned than perpendicular. 7. Bulk motion of cold He+ and H+ (no cold O+ or He++). The ion velocity (20km/s, duskward) agrees with the ExB velocity.

  27. (2) TOF mass analyser: He+ rich Composition 06:44:00 UT 06:48:30 UT H+ He++ He+ O+ contamination No oxygen! 0643 0644 0645 0646 0647 0648 0649

  28. He+ convection  ExB velocity ExB drift velocity = 25~50 km/s 4-15 eV for H+ => 15-60 eV for He+ 60-250 eV for O+

  29. Detail on Ion dynamics 15-60 eV for He+ 4-15 eV for H+ Cold ion moving in one (perpendicular) direction  (spin)

  30. // Ion drift direction vs E  drift direction Y (duskward) - UxB (estimated E) direction X (sunward)  U ≈ -ExB in direction (but no guarantee of frozen-in

  31. Observation Summary (06:43 UT) 1. Sudden change in particle flux (>40 keV, >10 keV, and <100 eV) when aurora bulge arrived Cluster’s conjugate ~19 MLT. 2. Change is simultaneous at all SC (SC-3 leading by 1~10 sec). 3. Simultaneous DC field change (tailward E~8mV/m, Pi2-like rarefaction |B|≈|BZ| up to 20%) without special wave activity. 4. Increase in medium energy (~100 keV, mass dependent) ion flux. Diamagnetic effect by ∆PP can quantitatively explain ∆PB. 5. Decrease in energetic e- (>30 keV) and ions (> 0.1 MeV) 6. Temporal (about 1 min) change of pitch-angle of 10-40 keV to more field-aligned than perpendicular. 7. Bulk motion of cold He+ and H+ (no cold O+ or He++). The ion velocity (20km/s, duskward) agrees with the ExB velocity.

  32. Indications (conclusion) E-field propagates together with the auroral bulge at ground, which is in the same direction as convection direction. cold He+ flux >> cold O+ flux: plasmaspheric He+ at 4 RE. No local acceleration: Mass dependent drift ? How did they come on time? Large-scale configuration change: pseudo-onset? Energy source? / Can minor auroral activity produce ring current ions?

  33. ion-scale ? All SC should observe the same behavior of ions if ion gyro-radius (RB = mv/qB) >> inter-S/C distance RB for B ≈ 200 nT condition

  34. consolation S/C distance ≈ 100 km in z direction & 50 km in x-y direction ≈ RB for 10~20 keV H+ << RB for Ring current ions  H+ > 20 keV (O+ > 2 keV) should behave the same at all SCs if the gyrotropic assumption is correct

  35. But, there is inter-SC difference RAPID (SSD) data

  36. Inter-SC difference: trapped H+ for CIS

  37. inter-SC difference ! For flux increase: (1) SC-2 < SC-1 < SC4=SC3 H+: 80~160 keV He+: 200~300 keV (2) SC-2 > SC-1 > SC4=SC3 H+: ~60 keV O+: 500~600 keV Hybrid: (5) SC-2 > SC-1 > SC4 > SC3 O+: 400~500 keV For flux decrease: (3) SC-2 < SC-1 < SC4=SC2 He+: 400~700 keV (4) SC-2 > SC-1 > SC4=SC3 O+: ~400 keV

  38. Look at more carefully: energy dispersion

  39. Energy dispersion = magnetic drift? orshell shift?

  40. End Now is the time to analyse/simulate Inter-SC difference of energetic particles with ion gyro-radius (RB) >> inter-S/C distance

  41. next is 06:48 event

  42. IMAGE/FUV 06:26~06:56 UT ~06:43 event ~06:48 event S/C 06:26 UT 06:34 UT 06:42 UT 06:50 06:28 UT 06:36 UT 06:44 UT 06:52 06:30 UT 06:38 UT 06:46 UT 06:54 06:32 UT 06:40 UT 06:48 UT 06:56

  43. all at 06:48:30 UT (12s resolution) SC-1: leading All info 25~150 eV 5-25 eV ET PA 25~150 eV 5-25 eV SC-3: 60s behind SC-1 25~150 eV 5-25 eV ET PA 25~150 eV 5-25 eV SC-4: 25s behind SC-1 ET PA O+ 30~500 eV 0642 0644 0646 0648 0650 0652 0654 0656

  44. Observation of event #2 1. Simultaneous at SC-1, 4 and -3 within 1 sec sudden activation 2. Bi-directional along B, and DC E-field disturbancedoubleparallel potential is carried by convection? 3. Wave with randomly changing Pointing flux direction (not shown here) wave is caused by the bi-parallel beam 4. Decrease 5~70 keV large-scale configuration change 5. More O+ than He+ not from cold plasma 6. Filamentation in the transpolar arcbut, the relation is not clear (?) 7. Only minor magnetospheric activityWhy do we observed only once in 5 years ?

  45. no wave@06:43 UT, wave@06:48 UT 150 nT  ΩP = 4 Hz ion dE dB S// E/B ΩHe? dBZ BB-EM spin effects stagnant dBX

  46. energetic component change: < 70 keV only

  47. Composition from energy ratio (1) From energy peak: plasmaspheric He+ rich //  Precursor (06:44 UT) Heating (06:49 UT) • = 0° • = 180° • = 360°  // H+ He+ O+ 18eV 70eV H+ He+ ratio=4: O+/He+ or He+/H+ 10 100 [eV] 10 100 [eV]

  48. End

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