cusp O+ H+ e- "SPI" event #1 event #2 MLT energy ratio = 15~20 O+ H+ 68°CGLat66°CGLat 63°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 ??? event 13 MLT IMF By ≈ -50 nT Kp=7+ Major storm-time (A) Unusual O+ injection

"wedge"event #3 (1)(2)(3) 9 MLT 10 MLT O+ H+ e- 60°CGLat66°CGLat P/A=0~90 ° P/A=90~180° P/A=40~140° O+ radiation belt? 63°CGLat event 9 MLT Kp=6- Major storm-time #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 ???

correlated & anti-correlated (1) O+ source ≠ H+ source (B) H+/O+ in the major return route (2) O+ motion ≠ H+ motion H+ 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+ H+ O+ appears earlier than H+. Drift of O+ is not bounce-averaged motion seen from pitch angles,

(C) Roles of escaped O+ Earth ? Mars ? Venus ? Io & other Satellites? (1)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.

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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

Cross-disciplinary importance of O+ circulation * Evolution of Earth, planets, satellites * Modeling of ancient Earth * Atmospheric environment * Chemistry of reservoir (CO 2, SiO 2, SO) * Basic plasma physics * Solar-terrestrial physics (energy and mass transfer) * General plasma/neutral circulation in the exosphere 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 ion escapeH+H+ O+O+ < 10 eV (2~3 Re)2~5 1~3 > 10 eV (3~4 Re)2~8 1.5~20 ion precipitationionelectron > 10 eV (DMSP)0.2~0.99~60 in /s mass budget H+H+ O+O+ meteors out 0.05~ ~5 - in < 0.02 ??? 0.5 in kg/s After Moore et al., 1999

Examples of O+ escape 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) Cluster: non-thermal O+ escape from the ionosphere [Nilsson et al., 2004]. H+ O+ H+ e- O +,O 2 + O+O+ H+H+ EM-matrix ET spectrogram Freja: Escape of ions (mostly O+) due to wave- heatings (three types) [Norqvist et al., 1998].

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

(1a) Most injection events occur in the nightside 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. Freja data ~

cusp O+ H+ e- " SPI " event #1 event #2 11 MLT 12 MLT13 MLT 14 MLT energy ratio = 15~20 O+ H+ 68°CGLat66°CGLat63°CGLat

"wedge" event #3 (1) (2) (3) 9 MLT 10 MLT O+ H+ e- 60°CGLat66°CGLatP/A=0~90 ° P/A=90~180° P/A=40~140° O+ radiation belt? 63°CGLat

(1b) Unusual events in the dayside #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 is unknown IMF By ≈ -50 nT, Kp=7+Kp=6- #2) O + injection (lower energy than H + ) adjacent to the cusp * Only this event * Freja-FAST discrepancy Generation 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

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

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.

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

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

Ion heating/escape (Freja example) [eV] [eV] O + H + Density e - Freja orbit 1798 ( ) — Transverse Acc. outflow — — Bulk plasma outflow —

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

Budget above the Earth's ionosphere ion escapeH+H+ O+O+ < 10 eV (2~3 Re)2~5 1~3 > 10 eV (3~4 Re)2~8 1.5~20 ion precipitationionelectron > 10 eV (DMSP)0.2~0.99~60 in /s mass budget H+H+ O+O+ meteors out 0.05~ ~5 - in < 0.02 ??? 0.5 in kg/s After Moore et al., 1999

Budget above the Earth's ionosphere ion escapeH+H+ O+O+ < 10 eV (2~3 Re)2~51~3 > 10 eV (3~4 Re)2~81.5~20 ion precipitationionelectron > 10 eV (DMSP)0.2~0.99~60 in /s mass budgetH+H+ O+O+ meteors out0.05~0.20.5~5- in< 0.02???0.5 in kg/s After Moore et al., 1999

We examined all heavy ion data of Freja satellite ( ) * 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).  From 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 (1) O+ injection events

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