Escaping ions over polar cap

Inner magnetosphere, Bow shock/Foreshock, and Ancient magnetosphere

Why? (1) Why do we research escape (2) Why do we research heating/energization (3) Why do we research Inner magnetosphere (low energy ions) (4) Why do we research bow shock / foreshock (5) Why do we research aurora (a) We are looking at phenomena that observations are not easily predicted by theories, and therefore are basic processes of plasma that needs to be understood (b) Inter-comparison between Earth-Venus-Mars = (1) and (4) (c) RBSP mission will intensify world-wide study = (2) and (3) (d) We are under aurora with ground-based facility = (2) and (5)

Inner magnetosphere Inner magnetosphere (Cluster observation): * We found cold source in addition to hot source energy in the tail (finished) * We found ionosphere source in addition to tail source (need 0.5 man- year) * We found equatorially-confined ions (need 1 man-year, on-going) * We derived the velocity of the drift from (need 0.5 man-year) * We found mass-dependent drift of energetic ions that no theory has predicted (need 1 man-year) * We found that some aurora is related to solitary structure in the inner magnetosphere (need 1 man-year). * We plan to study north-south asymmetric cases (need 1 man-year, on-going) * We plan to study contamination effect of the radiation belt particles (need 1 man-year)

Sub-to several-keV ion patterns in the inner magnetosphere (near perigee of Cluster) Viking Cluster westward drift eastward drift Perigee, 11 MLT 14 MLT poleward

6 MLT 9 MLT 12 MLT 15 MLT 18 MLT Time-lag (hours) Statistics: fossil of substorm (1) Moves eastward (2) Decrease in time for both probability and energy (Yamauchi and Lundin, 2006)

Further classification by two populations Peak AE during latest 6 hours vs Pattern in spectrogram Peak AE(a)(b)(c)(d) < 300 nT ~500 nT08171 > 500 nT53334 Pattern in Spectrogram

Warm (1 keV, 0.5/cc) Cold (0.2~0.6/cc) Observation Back-trace to 8 Re and Forward simulation finding out source

+1° 0°-1°-2° No Yes ? No S/C-4 S/C-1 S/C-3 Relative S/C position: all at 9.0±0.1 MLT 23:40-24:00 UT H+ O+ H+ O+ H+ O+

1000~2000 km E ions ≈ 3000 km/s ions > 5000 km/s keV P/A 06:4206:4606:4806:44 IMAGE (FUV)

Equatorial trapped 100 eV H+ (1) Trapped (pitch angle ~ 90°) and confined to Equator (2) nearly 50% in the noon and dusk sectors, and 35% in night-dawn. (3) Variable content of He +. (majority is less than 5%) (4) Variable energy ratio between He + and H + (1 to 4), contrasting to the previous report. (5) Time scale of about an hour.

Modeling Ancient magnetosphere/ionosphere

Prognosis of O/H ratio of atmospheric escape from non-magnetized Ancient Earth Increase inEUV/FUVSWDPIMF  (IMF) SEP Jeans & Photo- chemical (H, He) ++same + Hydrodynamic (all)++ (regime change) same + Ion pick-up (H, He)(#1)+same+ Wave and E // (all)++ (cf. Earth) + (cf. Earth) same+++ Momentum transfer (all) +++same++same O/H ratio of escape+ (#2)+same++ #1) depending on relative extent of ionosphere and exosphere #2) because non-thermal > thermal for Earth-sized planet

Mars-Venus-Earth difference 2: Bow shock and foreshock * Planetary size matters, Earth ≈ Venus ≠ Mars (no foreshock) because of (1) Gyroradius ≈ bow shock size for Mars (2) Extended exosphere due to low gravity produces cold ions at bow shock (3) This makes Mars an ideal laboratory to study micro-scale physics, i.e., ion motion. For example, we need new classification of shock. * Future plan (3-5 years) (1) bow shock reflection statistics (He++/H+ ratio etc) (2) comparison with cold ion

Venus-Mars difference For Mars: R S ~ 5000 km for Martian Subsolar 2 keV H + under 6 nT  r g = 1000 km 5/cm 3 H +  c/  pi = 100 km (1) size: finite gyroradius effect (2) cold ions: only Mars has cold ion at bow shock SW parameter R S (BS radius) M A (  n 1/2 V/B) c/  pi (  n -1/2 ) & c/  pi R S r g (  V/B) & r g /R S Venus111 & 1 Earth~ 5~ 1.2~ 1.7 & ~ 0.3~ 2 & ~ 0.4 Mars~ 0.5~ 1.4~ 3 & ~ 5~ 4 & ~ 8

Foreshock (Venus/Earth=yes, Mars=no)

Martian specialty on Bow shock acceleration

QTQLFSQT  & // acceleration  acceleration oblique acceleration // acceleration escape

on-going works old works

Foreshock: He++ and H+ show different behavior

inbound-outbound asymmetry: Quick ExB drift

Heating event

Freja O+ injections O+ = not well-studied H+ = well- studied in 1° x 1h bin.