Astronomy Hypertext_ Sunspots and the Sunspot Cycle -...

Unformatted text preview: 1/15/12 Astronomy Hypertext: Sunspots and the Sunspot Cycle As tronom H perte t Sunspots and the Sunspot C cle Lat est Modif icat ion: Jul 24, 2002 Suns pots and Suns pot Groups Da fea e he S ha e bee e ed f a ea 2000 ea . Se e a igh i g e ce a e c ai ed i a cie Chi e e ec d . A h gh he fi igh i g ec ded i E e, Ga i e ' e e c ic b e a i i 1610 ided he fi de ai , he c ic fa be f a ie he e a be f d i he a a he e. A ica sunspot ha a ce a c e i h a da ce e , he umbra, ded b a g a i h fi a e a egi , he penumbra. A h gh e i adia i , he b a da beca e i i ee agai a e e b igh e h he ic bac g d, h e e e a e i e 1800 K highe . The b a i ab e- f h a b igh a he h he e a d he e b a ab h eef h a b igh . S de e The g a id ie a i i a b a a ge a dia e e . S ab 1 ee . A 50,000 i dia b id i g de g i a a e fh a a e i he i e g a a egi f he h he e. , a d he ge e a f i c e , a i g a sunspot group, h e i ae aa e he a e a . Each e d f he g i f e d i a ed ded b ae . The e a ge g ac e e- fif h he ei e a g e i f e ea h , b a ica ife i e i ica a ge i ag i e 10,000 ac ; e ce i a e a e e e , ab f i e he dia e e f he Ea h. I a ee hi a ge ai dia e e ; he i i e dec i e . I di id a ia cha ge f da da hi e he ai ai hei a cia i . Suns pot C cle M e ha a ce ag i a di c e ed ha c e a d g i a gh 11 ea c c e. Aga h f be e e i e h a c c e f hi ea a ia i . S ch a fig e h ha he heigh f cce i e a i a a e b i e a , a d he i e a be ee cce i e ea gh i c a ; he 11- ea e i d i a e gh a e age. Each sunspot c cl e e ih f i g a a i de a d 35 N a d 35 S, a d a he c c e ge e , f ce he e a i b h he i he e . The a i be f f he a e f i g a a i de a d 25 i b h he i he e . Whe he a f a c c e a e f i g ea 5 N 5 S, a fe agai f a a i de a d 35 N 35 S he a d he begi i g f a e c c e. M agne tic Fie lds in Suns pots physics.gmu.edu/~jevans/astr103/ /sun_atmosphereSunspots.html 1/3 1/15/12 Astronomy Hypertext: Sunspots and the Sunspot Cycle I e e a chi g, c ed fea e a e b e e a d g (Fig e 15.8d). The a e c e f ga h e ha e i de e i ed b c ed ag e ic fie d i e , i ce ae be he ce e f i e e ag e ic fie d . A e hi beca e f he Zee a effec (Sec i 12.5). I a fi ide ified i he ab i ie f ec a b Ge ge E e Ha e (1868- 1938) a he M Wi Ob e a i 1908. I he Zeeman effec , he e g h f he ag e ic fie d ca be de e i ed f he e a a i fc e f ab i i e , hi e he di ec i f he fie d i h b he e e f a i a i f he e c e (Fig e 15.5). The eadi g fa g (i he f a d di ec i f he S ' ai )a e ie i ai f he f ig .O i e a i ie a e i e h e f he ha d he d fa ba ag e . The i f ea e f he i e i e g h f he ag e ic fie d i ca ed a ga . The ea ed fie d e g h i e ceed ha f he Ea h' fie d b e e a h a d i e , bei g e e a h a d ga . I he S ' he a d he he i he e , a i ie f eadi g a df ig aea i e each he . Tha i , he a i f he eadi g i he he he i he e a be h ee i g i e c c e, he ea ha f he he he i he e i h ee i g. The i he e c c e he eadi g i be h ee i g i he he a d h ee i g i he he he i he e. Th ag e ic fie d a i e e e i b h he i he e i cceedi g c ce . A a h e, he S d e ha e a ge e a ag e ic fie d i e ha f he Ea h. B b a e agi g e a ca i ed a d i e e ag e ic fie d , e ge he i e i f a ge e a fie d a fe ie ge ha he Ea h' fie d, e e a ga . Mag e ic ea e e ha e bee ade f he S fai eg a e he a 25 ea . F hich i ha bee f d ha ag e ic fie d i he a egi e e e a i ea he i e f a i a. Th ha a ea be a ge e a fie d i bab he acc ai f face fie d ha ha e d if ed i he a egi . O igin of S n po A h gh a e ha e e a a i f beha i a d he ag e ic fie d he ea ha g i h i , he e e a a i a e c e e a i f i g i a e ec . A a a ii he e e a a i i he a e he e i fh a e c e ha hei di g a dh he a e ab e ai ai ha c di i f g a e i d f i e. Si ce e e g f f he c e egi , a f d f h f high- e e a e ga di g h df i he c e a d ei i a e e ic a diffe e ce i e e a e. The ea ha hi d e ha e a ea be he abi i f ag e ic fie d ha e i i he i e i f i hibi he f f he a e e g i he . The acce ab e he f a e ha he i e ac i f he S ' diffe e ia a i a d c ec i e i i he h d ge c ec i e be he h he e ge e a e a d he di a b- h he ic ag e ic fie d. A he ag e ic fie d i e a e ed a d e ched e a a diffe e a i de b he f f ga hich he a e a ached ( a i e chi g i a he e a , he e a i i if e ), he fie d i e e e a c i be be he h he e. If a i de e , a be f ag e ic fie d i e i b ed a d, ha i a che i he h he e, f i g a bi a g . physics.gmu.edu/~jevans/astr103/ /sun_atmosphereSunspots.html 2/3 1/15/12 Astronomy Hypertext: Sunspots and the Sunspot Cycle A a bipola n po g o p b eak p and deca , he field of he follo ing po mig a e o a d pola egion and e en all ne ali e he e i ing pola field, allo ing a ne one o fo m, i pola i e e ed f om he p e io c cle. The pe iod of comple e e e al of n po pola i i h 22 ea . Thi magne ic c cle i mo e eg la han he 11- ea c cle. Tha i , if one n po c cle e e o be 12 ea in leng h, hen he follo ing c cle o ld be clo e o 10 ea o ha hei m o ld be he 22 ea of he magne ic c cle. Cop right 1995 J. C. Ev ans Ph sics & Ast ronom Depart ment , George Mason Univ ersit Maint ained b J. C. Ev ans; j ev [email protected] physics.gmu.edu/~jevans/astr103/ /sun_atmosphereSunspots.html 3/3 ...
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