Title: Morphology of electron precipitation during auroral substorms
Abstract: A Study of auroral substorms using coordinated measurements of a number of parameters at Ft. Churchill, Manitoba (L = 8) in October 1963 has yielded interesting conclusions on the electron precipitation close to the northern auroral boundary, the morphology of which appears to follow closely the working model proposed by Akasofu. Extensions to this model are suggested that include high energy electron precipitation (>30 keV) as determined from X-ray measurements at balloon altitudes. During surges and auroral substorms near local midnight, very localized precipitation of electrons with a wide spectrum of energies produced a sharp northern optical and radio absorption border which moved rapidly northwards and contained the auroral electrojet. During the decay phases of the substorms, a region of high energy precipitation receded southwards in advance of the northern border of luminous aurora and appeared to be accompanied by the ionospheric electric current. In contrast to this, the optical northern border produced no noticeable auroral absorption or magnetic activity on its southward overhead passage later in the substorm. Systematic spectral changes near the border indicated a softening of the electron spectrum above 40 keV with increasing northward position (or increasing L value), in agreement with satellite observations. Highly structured enhancements of precipitation of high energy electrons occurred at times when small scale folds in auroral bands were reported during break-up and at times of occurrence of Type B aurora. Иccлeдoвaниe cyбштopмoв пoляpныч cияний пpи пoмoщ и кoopдиниpoвaнныч измepeний pядa пapaмeтpoв, в Фopт чepчилль, Maнитoбa (I = 8) в oктябpe 1963 г., пpивeлo к интepecным вывoдaм oтнocитeльнo элeк тpoнныч ocaдкoв вблизи ceвepнoй paзгpaничитeльнoй линии пoляpныч cияний, м opфoлoгиякoтopoй пoвидимoмy близкo cлeдyeт paбoчeь мoдeли, пpeдлoжeннoй aкacoфy. coвeтyeтcя paзвить этy мoдeль тaким oбpaзoм, чтoбы oнa включaлa ocaдки в ыcoкoэнepгeтичecкич злeктpoнoв (>30 keV), oпpeдeляeмыч coглacнo измepeниям Ч-лyчaми иa aэpocтaтныч выcoтaч. Bo вpeмя peзкoгo yвeличeния coлнeчнoй aктив нocти и cyбштopмoв пoляpныч cияний, cocpeдoтoчeнныe в oднoм мecтe ocaдк и элeктpoнoв, c шиpoким cпeктpoм энepгий, coздaли peзкyю ceвepнyю oптичecкy ю и paдиoaбcopбцию нa гpaницe, кoтopaя быcтpo пpoдвигaлacь в нaпpaвлeнии ceвepa и coдepжaлa элeктpocтpyю пoляpныч cияний. B тeчeниe фaз pacпaдa, зoнa выcoкoзн epгeтичecкич ocaдкoв oтдaлилacь к югy, yпpeждaя ceвepный кpaй пoл яpныч cияний и пoвидимoмy coпpoвoждaяcь иoнocфepным элeктpoтoкoм. B пpoтивoп oлoжнocть к этoмy, oптичecкaя ceвepнaя гpaницa нe пpoизвeлa никaкoгo з aмeтнoгo пoглoщeния пoляpнoгo cияния, или жe мaгнитнoй aктивнocти в cвoe м нaдзeмнoм движeнии к югy, в пoзлнeйший пepиoд cyбштopмa. cиcтeмaтичecкиe измeнeния oкoлo paзгpaничитeльнoй линии yкaзывaли нa cмягчeниe элeктpoннoгo cпeктpa н aд 40 keV, c вoзpacтaющим мecтoпoлoжeниeм в cтopoнy ceвepa (или вoзpacтaющим знaчeниeм L), coглacнo нaблюдeниям нaд cпyтникaми. Bыcoкocтpyкт ypныe ycилeния ocaдкoв выcoкoэнepгeтичecкич элeктpoнoв cлyчaлиcь в тe пepи oды, кoгдa oбнapyживaлиcь нeбoльшиe cклaдки в пoлocaч пoляpныч cияний вo вpeмя pacпaдa и в иepиoды пoявлeния пoляpныч cияний тиa B.
Publication Year: 1967
Publication Date: 1967-08-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 20
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