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(A) Unusual O+ injection

O+ H+ e-. event #2. (A) Unusual O+ injection. event #1. cusp. "SPI". 1994-2-21 event 13 MLT IMF By ≈ -50 nT Kp=7+ Major storm-time. MLT 11 12 13 14. O+ H+. energy ratio = 15~20. 63°CGLat. 68°CGLat. 66°CGLat.

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(A) Unusual O+ injection

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  1. O+ H+ e- event #2 (A) Unusual O+ injection event #1 cusp "SPI" 1994-2-21 event 13 MLT IMF By ≈ -50 nT Kp=7+ Major storm-time MLT 11 12 13 14 O+ H+ energy ratio = 15~20 63°CGLat 68°CGLat 66°CGLat • #1) Mono-energetic ion injection with O+ faster than H+ (13 LT) • VF source > 10 Re (TOF distance ~ 1 Re). • From the southern cusp (ionosphere) Mass-filtering mechanism ??? #2) O+ injection (lower energy than H+) adjacent to the cusp Only this event among > 100 cusp  Freja-FAST discrepancy Generation mechanism ???

  2. O+ H+ e- e- "wedge" event #3 1992-12-28 event 9 MLT Kp=6- Major storm-time radiation belt? 9 MLT 10 MLT 60°CGLat 63°CGLat 66°CGLat O+ O+ O+ (1) (2) (3) P/A=40~140° P/A=90~180° P/A=0~90° #3) Multiple dispersive O+ injections from a nearby source * In oblique direction * Non-gyrotropic distribution * Sudden localized anisotropic energization at < 1000 km. Generation mechanism is a mystery ???

  3. (1) O+ source ≠ H+ source (2) O+ motion ≠ H+ motion (B) H+/O+ in the major return route H+ O+ H+ H+ correlated& anti-correlated O+ O+ Correlation part means that H+ and O+ has the same bounce-average drift motion. Then, how can we understand the anti-correlation part just 15 minutes later? O+ appears earlier than H+. Drift of O+ is not bounce-averaged motion seen from pitch angles,

  4. (C) Roles of escaped O+ Mass loading at the exterior cusp : Extra deceleration of SW (2) Enhanced Hall effect: Because of quicker O+/e- separation than H+/e- separation  Electrons start to divert from the plasma flow at a larger distance for storm time tha non-storm time (critical thickness of the current sheet changes)  Storm-time reconnection & current disruption is faster than non-storm-time reconnection & current disruption. Earth ? Mars ? Venus ? Io & other Satellites?

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  6. Returning O+ from the Magnetosphere to the Ionosphere M. Yamauchi (Swedish Institute of Space Physics, Kiruna) and Viking-V3 / Freja-F3 / Cluster-CIS teams (1) We surveyed heavy ion injections at 1700 km (Freja) altitude * Mostly found in nightside subauroral region. * We show three of them the rare (few %) dayside events (2) We found O+/H+ difference in the sub-keV ring current plasma * Evidences of source difference between O+ and H+ * Drift average for H+ whereas non-drift average for O+ (3) Roles of escaped O+ : cusp mass-loading and tail reconnection

  7. * Evolution of Earth, planets, satellites * Modeling of ancient Earth * Atmospheric environment * Chemistry of reservoir (CO2, SiO2, SO) * Basic plasma physics * Solar-terrestrial physics (energy and mass transfer) * General plasma/neutral circulation in the exosphere Cross-disciplinary importance of O+ circulation in 1025 /s in kg/s After Moore et al., 1999 Fact: # O+ escapes a lot (1~10 kg/s from Earth/Mars) # O+ behaves differently from H+ (for return) # But O+ return is not well studied

  8. Examples of O+ escape H+ O+ O+ H+ e- ET spectrogram Cluster: non-thermal O+ escape from the ionosphere [Nilsson et al., 2004]. H+ O+,O2+ EM-matrix O+ Phobos-2: O+ escape from Mars [Lundin et al., 1990]. High escape rate : 0.1 ~ 1 kg/s (obs. by Mars Express and Phobos 2) Freja: Escape of ions (mostly O+) due to wave-heatings (three types) [Norqvist et al., 1998].

  9. (1) O+ injection events O+ = not well-studied O+ H+ e- Freja observation of general ion injections in the nightside sectors O+ H+ e- H+ = well-studied Commonly-found ion injections near or equatorward of the nightside auroral zone.

  10. (1a) Most injection events occur in the nightside Freja data 1992.10 ~ 1994.10 Freja statistics shows clear nightside preference Not artifact of 63°inclination Some in dayside The total number of traversals with clear injection events in each bin is scaled by the size of the square. The numbers with # are the orbit number. in 1° x 1h bin.

  11. event #2 O+ H+ e- event #1 cusp " SPI " 11 MLT 12 MLT 13 MLT 14 MLT O+ H+ energy ratio = 15~20 68°CGLat 66°CGLat 63°CGLat

  12. event #3 O+ H+ e- e- "wedge" radiation belt? 9 MLT 10 MLT (1) (2) (3) O+ O+ O+ P/A=40~140° P/A=90~180° 60°CGLat 63°CGLat P/A=0~90° 66°CGLat

  13. 1992-12-28 1994-2-21 (1b) Unusual events in the dayside IMF By ≈ -50 nT , Kp=7+ Kp=6- #1) Mono-energetic ion injection with O+ faster than H+ (13 LT) VF source > 10 Re (TOF distance ~ 1 Re). ÞFrom the southern cusp (ionosphere) Mass-filtering mechanism is unknown #3) Multiple dispersive O+ injections from a nearby source * In oblique direction * Non-gyrotropic distribution * Sudden localized anisotropic energization at < 1000 km. Generation mechanism is a mystery #2) O+ injection (lower energy than H+) adjacent to the cusp * Only this event * Freja-FAST discrepancy Generation mechanism is unknown

  14. (2b) O+ motion ≠ H+ motion H+ O+ H+ O+ H+ O+ H+ obeys bounce-average, whereas O+ shows non-averaged effect

  15. Summary 1. There are more mechanism of ion escape/return from/to the ionosphere than a simple thought. Even now, we have many un-understood ion escape/return mechanisms.

  16. Mars: unexpected high loss rate ~ 1 kg/s vH+ nH+ nO+ nO2+ Lundin et al., 1990 Even higher flux is observed for the Earth (100~500 ton/day).

  17. Mars: quick energization of O+ is confirmed Lundin et al., 2004

  18. Ion heating/escape (Freja example) Freja orbit 1798 (1993-2-19) [eV] 103 101 103 101 O+ H+ Density e- — Bulk plasma outflow — — Transverse Acc. outflow — 10 0.1 [eV]

  19. O+ injection : it returns (we don't know the amount) Yamauchi et al., 2005

  20. Budget above the Earth's ionosphere in 1025 /s in kg/s After Moore et al., 1999

  21. Budget above the Earth's ionosphere in 1025 /s in kg/s After Moore et al., 1999

  22. (1) O+ injection events We examined all heavy ion data of Freja satellite (1992.10-1994.10) * Most injection events occur in the nightside * Some unusual events in the dayside (1) Mono-energetic injection with O+ faster than H+ (13 LT) VF source > 10 Re (TOF distance ~ 1 Re). ÞFrom the southern dayside ionosphere (cusp) Mass-filtering mechanism is unknown (2) O+ injection (lower energy than H+) adjacent to the cusp Freja-FAST discrepancy Generation mechanism is unknown (3) Multiple dispersive O+ injections from a nearby source In oblique direction with non-gyrotropic distribution Sudden localized anisotropic energization at < 1000 km. Generation mechanism is a mystery

  23. (2) H+/O+ in major return route (2a) O+ source ≠ H+ source correlated & anti-correlated

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