Statistic study of magnetosphere response to magnetic clouds: INTERBALL multi-satellite observations

Phys. Chem. Earrh (C), Vol. 25, No. l-2, pp. 177-180,200O 8 1999 Elsevier Science Ltd All rights reserved 1464-1917/00/$ - see front matter

Pergamon

PII: S1464-1917(99)00065-3

Statistic Study of Magnetosphere Multi-Satellite Observations

Response to Magnetic Clouds: INTERBALL

Yu. I. Yermolaev’, G. N. Zastenker’, N. L. Borodkova’, R. A. Kovrazhkin’, N. S. Nikolaeva’, M. N. Nozdrachev’, S. I? Savin’, A. A. Skalsky’, L. M. Zelenyi’, Z. Nemecek’, J. Safrankova’ and J.-A. Sauvaud3 ’

‘Space Research Institute, 117810 Moscow, Russia 2Charles University, Prague, Czech Republic 3CESRKNES, Toulouse, France Received 27 October 1998; revised 15 March 1999; accepted 20 March 1999

Abstract. features related to the interaction of !3ewrdunusua,l magnetic clouds with the Earth’s magnetosphere as observed on the INTERBALL sateliites during 1995-199’7 are dkussed. The main cause of magnetospheric disturbances is high pressure pulses on leading and trailii edges of clouds. Interaction of clouds with the magnetosphere results in its compreesion and deformation, large scale motions of the magnetic tail and initiations of substorms and storms. Several important consequences of theee processes were (1) observations of magnetospheric regions and boundaries much closer to the Earth than on average; (2) increases of density and temperature in outer regions of magnetosphere; (3) multiple crossings of geomagnetic tail boundaries presumably due to tail flapping, and (4) bursty fluxes of high energy ions and electrons in the auroral region and polar cap. 0 1999 Elsevier Science Ltd. All rights reserved. 1

2

of magnetic

clouds

An example of strong MC observed on January 10-11, 1997 on WIND are presented by Burlaga et al (1998). The magnetic cloud has certain features in common with another MC: high and rotating magnetic field B, low density N and temperature T between dense leading and trailing edgea of MC which are different from quasistationary solar wind (SW). The leading edge was preceded by the interplanetary shock. Specific features of the magnetic cloud were an extremely high density on the traiimg edge connected with solar filament and a magnetic hole observed also on trailing edge. Dates of magnetic clouds and durations of their observations near Earth as well as space regions observed by INTERBALL-1: SW - solar wind, MSH - magnetosheath, MS - magnetosphere (lobes, plasma sheet, neutral sheet, and low- and high-latitude boundary layers) are presented in Table 1. In addition to MC durations we indicate also time between interpianetary shock up stream MC and MC leading edge. In six cases INTERBALL-l satellite allowed us to observe d8erent regions of magnetosphere. INTEHBALG2 measured parame ters in the polar magnetosphere. Fe&urea of magnetic clouds and satelites’ orbits relative to magnetosphere changed from case to case. This allowed us to investigate behaviour of different parts of magnetosphere under different interplanetary conditions.

Introduction

The solar wind transkrs energy fkom the Sun to the Earth’s magnetosphere (MS) and one of the most important problems of the Solar-Terresrial Physics is what reactions of magnetosphere are caused by changea in the interplanetary medium (Akasofu (1980); Kamide and Slavin (1986)). The strongest disturbances of the s+ lar wind (particularly, the magnetic clouds) are usually generated by the coronal mass ejections, and an influence of magnetic clouds on the magnetosphere has been widely studied in the literature (see reviews by Burlaga (1991); Webb (1995), CXL Special Issue, 1998, No 14, and references therein). Here we review the interaction of magnetic clouds (MC) with Earth’s magnetosphere as observed on INTERBALL(Tail Probe) and -2 (Auroral Probe) satellites during 19951997. Cowqwmdence

Brief description

3

GeoefBciency

of magnetic

clouds

Passagea of MCs resulted in strong MS disturbances observed with ground-based magnetometers. Table 2 shows Dst index (geomagnetic storms) and substorms and activations (SBS&A) during MC interactions with MS. During studied time intervals Dst index was from 56 to - 124 nT (average value N -83 nT) and 54 SBs&As were observed. We used the Auroral Oval Indices plots

te: Yu.I.Yermolaev 177

Yu. I. Yermolaev et al.: Statistic Study of Magnetosphere Response to Magnetic Clouds

178 ‘Ihble N

1. Magnetic clouds observed on INTEBBALL/Tail Date

Durations,

h

MC

(+ Shock)

Probe aa well ae on WIND (*) and SOHO+IMP-8

Space regions by INTERBALL

Comments

1

1995 O&l&19

*

27

(+8)

MS/MSH/ MS

Multiple MP crossinga

2

1997 Jan.l&11

*

25

(+4).

MS/MSH/MS

3 4

Feb. 411 *

41

SW/MSH/MS/MSH/SW

SW N ~156 cm-S Flank BS crossings

Apr.lo-11

*

21

(14) (+5)

5

Aug. 3-4 *

13

(+3)

SW SW/MSH/SW

Sharp B, change BS and MP crossings

6

Sep.&20

*

56

(+3)

MS/MSH/MS

BS and MP crossings

7

Oct. 1-2 **

43

(+3)

MS/MSH/MS

Lobes and PS

32

(+6)

Average

(see home page of Cluster/Ground-Based Data Center http://www.wdc.rl.ac.uk/gbdc/ovals/plots/) to determine the times of SBS&As. Figure 1 shows the Oval Indices plot for January 10,1997.

were observed and rn from them were accompained by SBS&As; for B, <0 there is no value k). On the other side, several strong SW and IMF disturbances did not result in SBS&As. For example, the very large pressure and density jump on the MC trailing edge on January 11,1997 (see Burlaga et al (1998)) did not generate any large geomagnetic disturbance while magnetopause (MP) was displaced on 6 BE relative to its average position, and large-scale motions of geotail were observed. Figure 2 presented the ion observations for three orbits of INTERBALL in sequence (before, during, and after the passage of MC on January 6-7, 411, and 13-14, 1997) in the regions where usually the plasma sheet is observed, allows us to make conclusion about different behaviour of plasma and multiple spacecraft crossings of different plasma regions and boundaries.

4

Fig. 1. The Aurora1 Oval Indices (like AL index) for three gee magnetic latitude lines and the longitude of wed stations.

Comparison of SBS&As with MC structure (see for instance Figure 1 in the paper by Burlaga et al (1998)) showed that only 38 from 54 SBS&As (70 % total number) may be connected with shock before leading edge of MC (Shl), leading (LE) and trailing (TE) edges, shock before TE (Sh2), IMF B, sign (B,
(**)

Magnetosphere ing MCs.

(MS) boundary

locations

dur-

We compared MS boundary locations - bow shock (BS) and magnetopause (MP) - with their average position for interplanetary conditions P = 2.1 nPa and B,= 0 nT. Results of this analysis are presented in Table 3. Shape and motion of MP for MC on January lO-11,1997 are studied by Nikolaeva et al (1998) and Safrankova et al (1998). In the most cases, BS and MP were observed closer to the Earth than usually during passage of leading and trailing edges of MCs and farther during passage of rare plasma inside MCs and the best agreement between MP models and observations was obtained for model by Shue et al (1997). Obtained results indicate that compression of MS and its boundaries were generated by SW pressure increasing in leading and trailing edges of MCs. For January 10-11, 1997, Nikolaeva et al (1998) and Yermolaev et al (1997) showed that the MCs force much more complicated deformation than the simple compression when different MS regions experience proportional change in

Yu. I. Yennolaev et al.: Statistic Study of Magnetosphere Response to Magnetic Clouds Table 2. Geoe&Ciency of magnetic ClOud6’ StNCturaS Number of Substurmn aud act&&us Dnt, nT Date Shl LE B,jump BI
Sh2

TE

l/l

O/l

O/l o/o o/o o/o o/o o/o l/2

O/l l/l l/l O/l l/l O/l 3/7

179

1995 0~3.

~6 la Oct. 19 4-S 1997 Jan. 10 2-3 Jan. 11 ~6 Fob. a 3 Fob. 9 2-3 Feb. 10 4 Feb. 11 3-6 Apr.lCkll Aug. 3 -2 - -4 Aug. 4 2 1 Sept. la 7 -3-+3 Sept. 19 Oct. 1 2 1 Oct. 2 * Distance ie poasitive if boundary was located nearer ccmditious to the Earth than under average

‘~-l-L...-.--,

.

.

mm68m

~PJloQI

1

r-~~-.v--c

wm

awiR

Rtm

Mm

Tf!whuf

Fig. 2. INTEBBALL/‘Ikil Probe data for Jauusry 06-15,1997: energy ion spectra (Yermolaw et al ,1997).

the scales. For October U-19,1995, Savin et al (1997) obtained indications that reconnection in MP was lo cated at farther distance X than -20 RE. S

Plasma populations

inside MS during MC%

Several unusual katures observed in plasma characteristics during passage of MCs are following. - Observations of very hot (for instance on January lo-11,1997 (Yermolaev et al ,1997,1998)) as well as very cold (on October 19, 1995 (Savin et al , 1997))

plasma in MSH. - Very dense (N N 150 cmw3) plasma in MSH on January 11,1997 ((Niilaeva et al, 1998)) and absence of direct correlation of MSH and PS density ( (Yermolaev et al , 1997, 1998)) - LLBGlii plasma at large distance (- 8&) from geomagnetic equator (see Figure 2) (Yermolaev et al , 1997,1998). - Oscillation of geomagnetic tail structurespast satellite (see Figure 2 ; sequence of lobe and PS observations on January l@ll, 1997 indicates a tail motion (Yermo laev et al, 1997,1998)). - Acceleration of ions and electrons in the plasma sheet and their injections in the polar cap (Fiie 3 shows electron measurementsduring 3 consecutive orbites on January W-12,1997 (Yermolaev et al , 1997)).

6

Dhcussion

and conclusions

Presented data on interactionsof seven magnetic clouds with the Earth’s magnetosphere as obsereved on IN-

180

Yu. I. Yermolaev er al.: Statistic Study of Magnetosphere Response to Magnetic Clouds

turea

pastsatellites;

- acceleration of ions and electrons in the plasma sheet and their injections in the polar cap. Behaviour of the Earth’s magnetosphere under extremal interplanetary conditions observed during passage of strong magnetic cloud is not good described by current models and calls for further investigations. Acknowledgment The authors thanks S.I.Klimov and S.A.Romanov for providing the Tail Probe magnetic field data, as well as A.O.Fedorov and P.E.Eiges for help and useful disctisions. The WIND and IMP 8 magnetometer data (R.P.Lepping, Principal Invistigator) and plasma data (K.W.Ogilvie, A.J.Lazarus, Principal Investigators) were provided by NSSDC. The work was supported in part under INTAS Grant 96-2346 and BFFI Grants 95-02 03998,98-0216297,98-02-17402. References

Fig. 3. INTERBALL/Aurofal Probe data for January l&12, 1997: energy electron spectra (Yermolaev et al , 1997).

TERBALL satellites allow’us to make several concluSiOllS.

Geoef$ciency of magnetic clouds is the same as similar solar wind changes without clouds and depends on prehistory of interplanetary magnetic field. After longliving external driving (southward Bs IMF) almost all changes in solar wind pressure or returning IMF may result in auroral activations, substorms or storms (see Table 2). Under long-living northward B, IMF all magnetic clouds’ changes are likely to be not geoefficient. Thii conclusion is in good agreement with published papers (see, for instances, Chen et al (1996) and references therein). Thus, moderately high changes of magnetic cloud plasma and magnetic field parameters result in usual responses of magnetosphere to the similar interplanetary disturbances without passages of magnetic clouds. Extremly stiong jumps of parameters near MC boundaria (shocks, leading and trailind edges) result in unusual responses: - strong and complicated magnetospheric compression (with large boundary displacements) relative to usual position; - laraeamr&ude

oscillations

ofmmagnetic

tail struc-

Akasofu S.-I. The solar-wind magnetosphere anergy coupling and magnetospheric dieturbances, PlonetSpace Sci., Z?S,496, 1966 Burlaga L.F. Magnetic cloude, in Physic8 of the Inner Heliosphem, 1991 BurIaga L., R.Fitzenreiter, R.Lepping, K.OgIlvie, A.Ssabo, A.Laasrus, J.Steinberg, G.Gloeckler, R.&ward, D.Michels, C.l%rrugia, R.P.lin, D.E.Lamon, A magnetic cloud containing prominance material: January 1997, J.Gwphy.Res., 103, No Al, 277-265, 1996 Chen J., P.J.Cargill, P.J.Palmadeseo, Real-time identification and prediction of geoe&ctive solar wind structures, Gwphys.&s.Lett., 33, No 6,625, 1996 Kamide Y., J.A.Sisvin @de.), Solor Wind-Mognetosphen Coupling, Terra Sci., ‘Ibkyo, 1966 Nikolaeva N.S., G.N.Zaatenker, M.N.Nodrachev et al., AnaIysic of locations and motions of magnetopauee during passage to the Earth of magnetic cloud on January 10-12, 1997, Kosmidr.ZssIed,36, N 6, 1996 (in Ruseian, in press) Safr8nkova J., Z.Nemecek, L.Prech et al., The January lO11, 1997, magnetic cloud: Multipoint measurements, Gwphys.Reo.Z&, 35, N 14,2545, 1996 Savin S.P., O.Balan, N.Borodkuva et sl., INTERBALL magnet* tail boundary case studieg, Adu.Spoce Res., 80, N 4/5, p.999, 1997 Shue J.-H., J.K.Chao, H.C.Fu et al., A new function81 form to study the eolsr wind control of the magnetopause &e and shape, J. Gwphgir. Res., 1 Og, N 5, ~9497, 1997 Webb D.F. Coronal mass ejections: The key to major interplanetary and geomagnetic disturbances, Rev. Gcophys., Suppl., p.577, 1995 Yermolaev Yu.I., G.N.Zautenker, N.L.Borodkovs et al., Magnetic cloud event on 6-11 January, 1997: INTERBALL multi-eatellite and multi-inetrument obeervations, Pmt. 31.9t ESLAB Sump. “Correkrted Phenmen o ot the Sun, in the HeliwpheFe and in Gwapocev, ESTEC, The Netherlsnds, September, 1997, ESA SP-416, p.155, 1997 Yermolae~ Yu.I., G.N.Zestenker, M.N.Nosdrachev et al., Pl88ma popukations in the magnetoephere during the pm of magnetic cloud on 16-11 January, 1997: INTERBALL/Thil Probe ObeeTvBtions, Gwphye.&s.Lett., 85, N 14,%65, 1998