In this paper several polar cap absorption events, for which simultaneous riometer data exist for Thule, Greenland, and College, Alaska, are examined in detail in order to make a careful comparison of the ratio of absorption at the two stations. In addition, comparison with other stations both to the south and north of College is made. It is verified that one can divide the polar cap into two regions. In the first, including latitudes to the north of geomagnetic 65° (L = 5.5), the progress of the PCA event is dominated by the time variations of the solar particle flux, and is essentially independent of the geomagnetic field variations. The ratio of absorption College/Thule is usually found to be 0.8 or greater throughout the event.In the second zone, extending from geomagnetic latitudes of about 64° down to about 55°, the characteristics of the PCA are largely dominated by the influence of the geomagnetic field. It is shown that at L= 4.3, the pre-magnetic storm value of the ratio Farewell/Thule is about 0.14. However, during the magnetic storm, the ratio tends to approach unity. At King Salmon (L = 3.3) it is seldom possible to identify PCA prior to the magnetic storm, although the post-storm value of the ratio King Salmon/Thule may approach unity for sufficiently large magnetic storms (maximum Dst > 200 γ.The results of this study are compared with satellite studies of the solar particles and with the theoretical calculations of the absorption expected from protons with given exponential rigidity spectra.(1,2) These results lead to the deduction of an effective cutoff at College of the order of 30 MeV or less, as has been observed directly by satellites in a small number of events.In the present work, the magnetic activity is characterized by Dst. It is found that, in the second zone of PCA activity (the outer ring), the prestorm cutoffs are apparently restored at a greater Dst value than that corresponding to onset of the cutoff reduction at the beginning of the storm. The effect may be interpreted in terms of a progressive softening of the proton spectrum as the event progresses.B этoй paбoтe пoдpoбнo pвccмвтpивaютcя нe\́yeкoлькo cлyчaeв вб\́yeopбции пoляpнoй шaпиoй, для чeгo cyщe\́yeтвyют pиoмeтpичecкиe дaнныe для Tюля (Thule) в Гpeнлaндиo и Кoллeдзa нa Aляcкe. Эти иc\́yeлeдoвaния пpoизвoдилиcь для тoгo, чтoбы тщaтeльнo cpввнить cтeпeнь пoглoщeния нa этич двyч \́yeтвнцяч. Bдoбввoк cpaвниввют\́yeн двнныe дpyгич \́yeтвнций к югy и ceвepy oт Кoллeдзя. Пoдвepздвeт\́yeя, чтo мoзнo paвдeлить пoляpнyю щaпкy нa двe oблa\́yeти. B нepвoй, вкλючaя щиpoты к \́yeeвepy oт гeoмвгнитнoй 65° (L = 5.5), pвзвитиe aб\́yeopбции пoляpнoй щaпкoй пoдчиняeт\́yeя ввpивциям вpeмeни пoтoкa coлнeчныч чacтиц и, пo \́yeyщe\́yeтвy, нe зввиcит oт измeнeний в гeoмвгнитнoм пoλe. Oтнoшeниe пoгλoщeния в Кoллeдзe и Tюлe вo вpeмeнa вктивнo\́yeти oбыкнoвeннo paвянeт\́yeя 0.8 или нecкoлькo бoльщe этoй цифpы.Bo втopoй зoнe, pacпpocтpвняющeйcя oт гeoмaгнитнoй щиpoты пpиблизитeльнo oт 64° дo 55°, чapвктepиcтики пoглoщeния пoляpиoй щaнкoй глaвным oбpвзoм пoдвepгaют\́yeя влиянию гeoмaгнитнoгo нoлн. Пoкaaaнo, чтo пpи L= 4.3, cooтнoщeниe вeличин дo-мaгнитныч бypь Фapвeл/Tюль paвняeтcи пpиблизитeλьнo 0.14. Oднaкo вo вpeмeнa мaгнитныч бypь, cooтнoщeниe этo \́yeтpeмитcя к eдиницe. B Кинг-Caлмoн (L = 3.3) oчeнь peдкo мoзнo ycтaнoвить cтeпeиь пoглoщeния мвгнитнoй щвнкoй иeзaдoлгo дo мвгнитныч бypь, чoтя вeличинa cooтнoщeния Кинг- влмoн/Tюль пocлe cильныч мaгнитныч бypь (мaк\́yeимyм Doypя > 200 γ) мoзeт cтpeмитьcя к eдиницe.Peзyльтaты этич иccлeдoввиий cpaвниввют\́yeя c изyчeниeм coлиeчныч чвcтиц пocpeд\́yeтвoм cиyтникoв, и \́ye тeopeтичecкими pa\́yeчeтaми пoглoщeния, oзидвeмoгo oт пpoтoнoв co cпeктpaми c звдвннoй экcпoнeнтнoй зecткo\́yeтью (3,2). B Кoллeдзe эти peзyльтвты пpивoдят к дeдyкции зффeктивнoй кpитичe\́yeкoй знepгии нopядкa 30 Mзв (Meгa элeктpoи-вoльт) или мeнee, кaк нвблювлo\́yeь в peдкич cлyчaяч нeпocpeдcтвeннo cпyтникaми.B нacтoящeй paбoтe мaгнитнaя дeятeльнocть чвpaктepизyeт\́yeя пocpeд\́yeтвoм Doypя. Haйдeиo, чтo вo втopoй зoнe дeятeльнocти пoглoщeния пoляpнoй шaпкoй (нapyзнee кoльцo), дo-бypныe кpитичe\́yeкиe эиepгии пoвидимoмy вoccтaнaввливaютcя пpи б\́qoльщич зиaчeнияч Doypя, чeм cooтв\́yeтeтвyющиe пopoздeнию yмeньщeния кpитичe\́yeкoй энepгии виaчвлe бypи. Эффeкт зтoт мoзeт быть выpaзeн в знaчeнияч нpoгpec\́yeивнoгo pвзмягчeния cпeктpa пpoтoнa c paзвитиeм пpoцe\́yeca.