Полярные геомагнитные возмущения и связанные с ними явления : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая 1986 г., Суздаль / Междунар. геодез. и геофиз. союз, междунар. ассоциация геомагнетизма и аэрономии, АН СССР, КНЦ, ПГИ. – Апатиты : [б. и.], 1989.

P.I.Velinov, A.Popov, I.Mastikov, Chr.Spasov, M.Cohen, P.Nenovski, N.V.Kelitenkov ON THE PROCESS O P FLO W - A R O U N D THE MO O N FROM THE SOLAR W I N D AS A SOURCE OF MAGNETOSPHERIC DISTURBANCES I n t r o d u c t i o n . The pro b l e m o f magnetohydrodynamical lunar wake occuring due to the Inter a ction of the solar wi n d w i t h a super alfvenic velocity (Alfvenic M a c h number Ыд>4+20) w i t h the lunar pseudo-magnetosphere has not been clarified yet. Only w h e n the spaoesraft Explorer-35 (IMP-E) waa launched on Ju l y 19.1967 and placed into lunar orbit on July 22,1967 the first precise m e a s u rements of the nature of the interaction of the solar wind w i t h the M o o n we r e made /1,2,3/i These measurements showed that during the interaction of the solar wi n d wi t h the Mo o n there waa no formation of a bow shock wave on the no o n side of the Mo o n but a plasma wake was indicated on its night side. So, the M o o n haa b e e n r e garded as a nonmagnetic sphere w i t h a re l atively l o w conductivity wh i c h absorbs (or neutralizes) the solar plasma occured o n it. Thus, the presence of the M o o n does not disturb the interplanetary field lines except for in the free plasma region on the night side /1,2,4/. As a result a n vunbralis formed behind the M o o n that could not exist if the M o o n possessed a hi g h conductivity. The principal phenomena in the solar wake are /5,6/: a) a downwind plasma umbral cavity or void containing a n enhanced intensit y of the interplanetary magnetic field (IMF) ( < +30 %) only slightly perturbed i n the direction; b) a downwind penumbral region of a r a r e faction wave or Ma c h Cone, elliptical in cross sectional geometry, contains a r educed plasma flux and magnetic field ( > - 3 0 %); о ) a very limited penumbral region, upwind of the lu n a r M a c h Cone, sometimes contains enhanced ( < +30 %) magnetic fields and plasma fluxes. Although the data fr o m the Explorer-35 and their interpretation have widened our understanding of the i n t e raction between the solar w i n d and the M o o n there are some unresolved problems, f o r example: 1) Kfhat sort of source m e c hanism produces positive penumbral anomalies sometimes observed in the IMF? 2) H o w far b ehind the M o o n can its wake be detected and by what means? 3) Does the lunar wake effect exist on the Ea r t h magnetosphere and on w h i c h of its processes and parameters? Indeed e a c h geomagnetic phenomenon w i t h a period equal to the lunar sinodic period of 29.53 days can be re l a t e d to the magnetic field of the M o o n or to the lunar p seudo-magnetosphere wake as it is k n o w n that the solar wi n d disturbs the M o o n magnetic field strongly regardless of its origin. The object of this w o r k is to discuss some of these problems. The effect of the lunar wake on the magnetosphere disturbances has be e n studied using: a) coeparative analysis, b) correlative analysis, c) spectral analysis, and 4) theoretical analysis of small irregularities due to the lunar wake on the magnetosheath an d on the magnetopause during the ne w Moon. Comparative a n a l y s i s . The catalogue /1/ and the So]ar-Earth data /8/ have b e e n used as an initial base for the interplanetary medium parameters (the velocity V of the solar wind, the direction, and the IMF polarity). It is evident that the long tall of the night side of the M o o n appears to be 102