Sovremennye problemy solnechnoi fiziki
i
geliostereoskopicheskie eksperimenty
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4. Problema solnechnoi peremennosti >>
Delo v tom, chto kosmicheskaya pogoda nachinaetsya na
poverhnosti Solnca, istochnika izlucheniya i energichnyh
chastic, vliyayushih na Zemlyu.
Izmeneniya ishodyashego ot Solnca izlucheniya neposredstvenno
vliyayut na sostoyanie verhnei atmosfery i ionosfery cherez
vozbuzhdenie i ionizaciyu atomov i molekul. Korpuskulyarnye
potoki, idushie ot Solnca, vklyuchayut v sebya i energichnye
chasticy, i nizkoenergichnuyu plazmu, kotorye i sostavlyayut
solnechnyi veter. I chasticy, i elektromagnitnye polya po mere
dvizheniya ot Solnca evolyucioniruyut, osobenno kogda oni
obrazuyut mezhplanetnye udarnye volny ili vzaimodeistvuyut s
mezhplanetnymi udarnymi volnami. Solnechnyi veter duet ot
Solnca i stalkivaetsya s Zemlei. Plazma i magnitnoe pole
solnechnogo vetra vzaimodeistvuyut s geomagnitnym polem i
atmosferoi Zemli, obrazuya kaplevidnuyu oblast', nazvannuyu
magnitosferoi. Poverhnost' etoi oblasti nazyvayut
magnitopauzoi. Magnitopauza obychno nahoditsya na rasstoyanii
okolo 10 zemnyh radiusov (

) ot Zemli v napravlenii na
Solnce, hotya eto rasstoyanie mozhet sil'no menyat'sya (ot 5 do
15

) v zavisimosti ot dinamicheskogo davleniya solnechnogo
vetra. V antisolnechnom napravlenii magnitosfera
prostiraetsya do rasstoyanii, lezhashih za predelami lunnoi
orbity. Magnitopauza yavlyaetsya bar'erom, predohranyayushim
magnitosferu ot proniknoveniya vnutr' pochti vsei energii,
kotoruyu neset solnechnyi veter. Pri normal'nyh usloviyah
energiya, kotoraya vse zhe prosachivaetsya skvoz' magnitosferu,
sohranyaetsya v vide chastic i polei vnutri magnitosfery, no
pri nekotoryh usloviyah ona impul'sivno inzhektiruetsya v
atmosferu Zemli. Impul'snaya ezhekciya energii nazyvaetsya
magnitosfernoi subburei. Ona harakterizuetsya razvitiem
yarkih i dinamicheskih polyarnyh siyanii i poyavleniem
intensivnyh tokov v ionosfere. V period subburi
magnitosfernoe magnitnoe pole vnezapno prinimaet druguyu
formu, a posle subburi imeetsya period vosstanovleniya,
zanimayushii mnogo chasov.
Subburya - eto otnositel'no kratkovremennyi otklik
magnitosfery na vozdeistvie solnechnogo vetra. Bolee
dlitel'nymi, dolgo zhivushimi (ot neskol'kih dnei do nedel')
yavlyayutsya geomagnitnye buri, kotorye yavlyayutsya otklikom
vozdeistviya bolee prodolzhitel'nyh potokov solnechnogo vetra,
harakterizuyushimsya sil'nym napravlennym na yug mezhplanetnym
magnitnym polem. Geomagnitnye buri privodyat k zametnoi
energizacii chastic kol'cevogo toka, poyasov kvazizahvachennyh
chastic-elektronov, protonov i bolee tyazhelyh ionov, a takzhe
k zametnym fluktuaciyam geomagnitnogo polya v nizkih
geograficheskih shirotah. Magnitosfernye chasticy vysypayut v
polyarnye shapki, nagrevaya neitral'nuyu atmosferu (mezosferu i
termosferu) i generiruya ionosfernye vozmusheniya. Subburi
mogut poyavlyat'sya i na fone geomagnitnyh bur'. Posle togo
kak solnechnyi veter vozvrashaetsya k nevozmushennomu
sostoyaniyu, magnitosfere i ionosfere dlya vosstanovleniya
trebuetsya vremya ot neskol'kih chasov do sutok.
Bol'shinstvo magnitosfernyh processov proyavlyaet sebya v
izmeneniyah parametrov ionosfery i termosfery.
Magnitosfernye processy obrazuyut elektricheskie toki,
avroral'nye emissii, nagrev za schet treniya, ionizaciyu i
zamiranie radiosignalov. Vse eti yavleniya sostavlyayut
elementy kosmicheskoi pogody v okolozemnom prostranstve.
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