地球對太陽風暴的響應

太陽風的帶電粒子進入地球磁層的動態(tài)示意圖太陽風的帶電粒子如何進入地球磁層SolarwindparticlesarenotabletopenetratetotheEarth'ssurfacebutareforcedbythemagneticfieldtomovearoundtheEarth.ParticlesgainentrythroughthecuspsthatareshapedlikefunnelsoverthepolarregionsortheygainentryfardownstreamfromtheEarth.TheparticlesthatenterdownstreamtraveltowardtheEarthandareacceleratedintothehigh-latitudeionosphereandproducetheauroralovallightshows.OtherhigherenergyparticleradiationthatcouldposeadangertolifehereonEarth,isforcedtodriftaroundtheEarthwithintwolargedonut-shapedregionscalledtheradiationbelts.Invisiblemagneticfieldsarethereasonthatparticleradiationmovesinthisway.

上圖為用於表示磁暴強度的DST指數(shù)，此圖為2003年11月的磁暴紀錄，其中曲線大幅陡降處為磁暴的發(fā)生。其地磁變化幅度達500nT(nano-Tesla)，是少見的強磁暴事件。極光與磁副暴磁副暴發(fā)生時才會出現(xiàn)的明曜區(qū)域右圖為POLAR衛(wèi)星以可見光拍攝的極光橢圓圈(圖上的亮環(huán))，地球左上半球的明亮範圍是太陽光照射所致。POLAR以可見光拍攝之極光橢圓圈在磁副暴發(fā)生時的發(fā)展過程人造衛(wèi)星POLAR以極紫外波段(Ultraviolet)拍攝的極光於磁副暴發(fā)生時發(fā)展的過程，依序由左上向右，再由左下向右。人造衛(wèi)星POLAR以極紫外波段(Ultraviolet)拍攝的極光活動性之動態(tài)過程磁副暴發(fā)生時POLAR衛(wèi)星以X射線波段拍攝的南極上空極光之活動性2005/11/20地磁暴期間，磁副暴發(fā)生時極區(qū)磁場變化情形，圖中的極光橢圓圈區(qū)磁擾動指數(shù)分別有AU,AL,AE=AU-AL,AO=(AU+AL)/2等四種指數(shù)。電離層對地磁暴的反應Theatmosphere'sionizationlayersmakepossiblelongdistanceradiocommunicationbyreflectingtheradiowavesbacktoEarth.Theyalsoarehometotheauroraandthemega-amperecurrentsthatheattheatmosphereathighlatitudesduringgeomagneticallyactivetimes.Duringstormsdepletionsandenhancementsofionizationoccurdependingonthelocaltimeandgeographicallocation.Depletionsareparticularlyeffectiveatcausingproblemswiththenormaloperationofradiocommunications.精品課件！精品課件！Themovieisa24-hourlongsimulationofthetotalelectroncontentinacolumnabovetheEarth'ssurface(between100and400kmaltitude)duringtheApril10-11,1997ionosphericstormevent.Thisstormoccurredinassociationwithamagneticstormthatbeganinnear-Earthspaceat~21UTonApril10duetothearrivalofacoronalmassejectionfromt