Т Е М А

1. Инжекции плазмы нагеостационарную орбиту: зависимость от параметров плазменных струй и состояниямагнитосферы.V. A. Sergeev, I. A. Chernyaev, S. V. Dubyagin (SPbU), Y. Miyashita (STEL), V. Angelopoulos(UCLA), P. D. Boakes, R. Nakamura (SRI,Graz) M. Henderson (LANL)

2. Т Е М А Связь струйных течений в плазменном слое магнитосферы (BBF) с инжекциями энергичных частиц на геостационарную орбиту • Модели и Наблюдения • Модель плазменных струй (“bubble”) • Эксперимент: сравнение BBF  инжекции, роль величины энтропии плазменной трубки • Факторы, контролирующие глубину инжекции, прогноз возможной инжекции для GEO

3. Transient Injections into the inner magnetosphere - theory/simulations • Subsonic EM pulse model (Li et al.1998, Zaharia et al., Sarris et al.) - useful mathematical model, but - EM pulse origin is unclear • Plasma bubble model (Pontius and Wolf 1990, Chen and Wolf… , MHD simulations Birn et al.2004... RiceU group, reviews by Wolf et al.2009, Birn et al. 2009) • Bubble =plasma-depleted dipolarized fast-flow channel in closed flux tube region • Origin either (1) Magnetic reconnection production of low-entropy bubbles (Birn et al. JGR2011) , or (2) Interchange instab. in minB configurations (…Pritchett &Coroniti, 2011)  modest depleted tubes • pV5/3 in the bubble as important parameter, e.g., injection depth (Birn et al., 2009) Equatorial view (Birn et al., JGR 2011)

4. Plasma Bubble Scenario • Plasma tube entropy S  P V5/3 (V= ds B) - approx. invariant in the moving flux tube (exact in frozen-in plasma, ideal MHD) ?? • Polarization/FAC generation if SV0 (from Vasyliunas-Tverskoy theorem), • ji= Bi /2Beq z  [VP ]eq • = Bi /(2BeqV5/3) z  [V(PV5/3)]eq. • S provides integral measure of divergence of perpendicular plasma current • If cross-tail S exists, polarization  radial interchange motion • Depleted plasma tube (bubble) moves Earthward (BBF) • Generator for MI coupling  R1-type FAC, FA acceleration, streamers …(many evidence…) • Final destination (R0) depends on bubble entropy Sb (Birn et al., 2009)??

5. Transient Injections into the inner magnetosphere - observations • Observationally the relationship BBF/DIP  injection/DIP is not as obvious: • BBF braking/rebound/diversion is not well understood, but sometimes expected to operate at ~10 Re, e.g. Haerendel, Shiokawa … -. Probability of Earthward flow sharply decreases 97Re (Lee et al., 2011) injections to 6.6Re?) • Considerable part of BBFs do not produce injections • 2-SC comparison : Low penetration efficiency of BBFs (~30%, CL-TС1, dr~5Re,Takada et al. 2006) • Many BBFs do not produce DIP/injection at GEO (Ohtani et al.2006) • Many substorm onsets are not accompanied by GEO injections (30% in Boakes et al. 2011). • It is not sufficient to create fast flow channel , there should be another • factors/processes (another physics) which control the inward penetration of plasma (injections) . ROLE of Bubble ENTROPY !

6. Motivation of this talk • Test observationally two basic predictions of the bubble scenario concerning GEOinjections • Penetration distance depends on bubble Sb • Possibility of injection is controlled by S0 at destination place • Requirements • Registration in 2 points : inside flow burst and at GEO (injection) • Computation of S=pV5/3 at both locations Equatorial view (Birn et al., JGR2011) Tail configuration: stretched quiet

7. Plasma Bubble Scenario - Validation?Questions • How to evaluate V= ds B in Flow Burst based on SC observations? • Formula by Wolf et al. (2006) for V (x,y,Br,Bz,P) - by fitting many equilibr. configurations • Tested/validated in 3d MHD simulations Birn et al.(2011) • How to compute V & P, S at GEO?? • Using SW-based model (T96) , V – directly from T96, P –from integration • PGEO=  dx (jxB)x + P11Re. • (Tsyganenko-Mukai 2003 pressure model) • Validity of PV5/3 =const , esp. in the inner region magnetic drifts?, turbulence? • How does the entropy change during dipolarizations in the inner region? • Entropy (etc) change during dipolarizations in the inner region?

8. Experimental Setup & Data Base No injection Injection GEO Tail configuration: stretched quiet • #1 Geotail (8-12 RE, +/- 3h MLT) LANL (any MLT): • 1995-2005 ~60 with definite LANL events • Isolated Flow burst/DIP at the tail probe dBz>5 nT, >1, … • #2 THEMIS (~11RE, +/- 3h MLT) THEMIS (~9RE) radial pair • THEMIS (~11RE, +/- 3h MLT)  LANL (any MLT, blind test)): • 2008-2009 ~50 events (Dubyagin et al. GRL 2011) • same as before at the tail probe • Entropy S at tail probe - use V(p,x,y,Bx,Bz) from Wolf et al 2006 • Entropy at 6.6Re, 02 h MLT calculated from SW-based T96 model

9. #2 THEMIS pair: Examples, Flow Bursts as the bubbles No injection ~20% 8 events 11Re ? ~80% 34 events 119Re P3 P5 Injection P3 P5

10. #2 THEMIS pair : Entropy Test , 11 9 Re • peak Vx or Bz at tail probe are bad predictors • Entropy is best predictor of penetration to inner probe, still works in drift-dominating region • (Dubyagin et al GRL 2011)

11. #1 Geotail  LANL : • Flow Bursts as the bubbles • Superposed Epoch results (1min averages) • Common for bubbles/BBFs (e.g., Ohtani et al 2004) • Enhanced BZ, flow VX, flux transport Ey O • Depleted pV5/3 • Peculiar at ~9Re are • density/pressure depletion - less clear (1min?) • entropy control works 119Re (THEMIS) • GEO-penetrating flow bursts • Deeper |S| depletion and larger dBZ in penetrating FBs • Vx or Ey are bad predictors • Higher pressure before/during penetrating FBs – effect of background configuration

12. #1 Geotail  LANL : • Radial Dependence • GEO-penetrating flow bursts have • Deeper |S| depletion and larger dBZ • Higher pressure before/during penetrating • but: • Sb ( r ) ! (drifts?, systematic errors in S-computation?) • Nearest flow bursts are more effective ! %

13. Does penetration depend on • how stretched configuration is? Tail configuration: stretched quiet No injection Injection • Entropy at 6.6Re, 02 h MLT calculated from SW-based T96 model (+TM03 pressure) • Confirm that injection probabilty strongly depends on how stretched is the local configuration (in agreement with Takada et al. 2006, and Boakes et al.2011 results) • Suggest local entropy SGEO as convenient local parameter controlling the penetration distance (together with bubble entropy Sb) • Confirm the basic predictions of the bubble scenario

14. CONCLUSIONS Generally confirm flow bursts (BBF) as origin of transient injections to GEO • Direct support of “bubble” model (BBF) • Statistically Vx, dBZ  S at ~11Re • Injection 11Re9 Re predicted by Sb/Sin !! • Conditions for GEO injections • Penetrating injections have lower Sb • Vx or Ey – not important factor • Critical dependence on Configuration at destination place ( local Sin )!! • Practical way to predict - based on local Sin • GEO injections are not a reliable signature of substorm onset

15. Dec.16, 2006

16. Interpretation of R2 loop : MHD, RCM Generation of R2 currents during flow braking/diversion Birn et al.,JGR 1999, 2011; Yang et al. 2011 Question to modelers : quantitative relationship I1 / I2 , its variations Courtesy J.Yang RiceU R2 R1

17. BBFs as spatial structures Pre-Cluster view: • true convective flows in the CPS (plasma tube motion); time-scale 1-10min; basic contribution to PS transport; strongly related to SBS; may be MReconnection product • cross-tail scale ~2-3 Re – confirmed statistically by Nakamura et al. (2004 GRL, CL) • bubbles (turburlence?) Runov et al., GRL 2009; PSS 2010 TH (also Tang et al.,2010) BBF at SBS onset traveling 20Re11Re (27.02.2009) • BBFas individual meso-scale structure (not turbulence) conserved/ transported on macro- scales (~10Re, minutes) • Generic structural features : laminar compression layer, • sharp DIP front, • bubble proper (turbulent inside) ; • BZ, (T ) N, P, PV  plasma bubbles; • Vfront ~ Vpx ~ 300km/s , ?reconnection in embedded TCS? Consistent with statistical BBF properties (Ohtani et al.,JGR 2004, GT)