Ehangiad ardaloedd bywiog o’r Haul i’r gofod


Ehangiad ardaloedd bywiog o’r Haul i’r gofod
Huw Morgan

Mae gan yr Haul faes magnetig cymhleth sy’n ymdreiddio drwy’r ffotosffer (arwyneb yr Haul) i’r corona (atmosffer yr Haul). Ymddengys fod fflwcs magnetig newydd yn codi drwy arwyneb yr Haul ar ffurf dolenni caeëdig gydag un rhan o’r ddolen yn treiddio i’r ffotosffer, gan ehangu i’r corona. Mae’r broses yn nodweddiadol o ardaloedd bywiog yn y corona. Trwy gydol y broses, caiff y maes magnetig yn y corona ei greu a’i adnewyddu’n gyson. Mae hefyd yn bosibl i’r maes magnetig a phlasma (nwy trydanol egnïol) gael eu cludo allan o’r corona drwy lifo gyda gwynt yr Haul i’r heliosffer (y gofod yng nghynefin yr Haul sy’n cynnwys cysawd yr Haul). Ceir cludiant o’r fath yn ystod digwyddiadau ffrwydrol ar yr Haul. Yn ôl y llenyddiaeth gyfredol, ni cheir cludiant oni cheir digwyddiad ffrwydrol, ac felly pan na cheir ffrwydrad, disgwylir y caiff meysydd magnetig caeëdig ardaloedd bywiog y corona eu hynysu rhag yr heliosffer. Mae’r erthygl hon yn cyflwyno tystiolaeth wahanol i’r llenyddiaeth gyfredol. Mae’r arsylwadau a gyfl wynir yn dangos y dystiolaeth gyntaf y gall y maes magnetig caeëdig ehangu’n uniongyrchol o’r corona heb ddigwyddiad ffrwydrol gan ffurfio rhan bwysig o wynt yr Haul. Cesglir y dystiolaeth drwy gymhwyso technegau delweddu newydd i arsylwadau o’r corona. Cyflwynir yr arsylwadau a thrafodir eu goblygiadau i’r darlun cyfredol a geir o’r prosesau sy’n cysylltu’r Haul â’r heliosffer.


Cyfeiriad:

 
  	Huw Morgan, 'Ehangiad ardaloedd bywiog o’r Haul i’r gofod', Gwerddon, 18, Medi 2014, 10-22.
   

Allweddeiriau

 
    Haul, ffotosffer, corona, maes magnetig, fflwcs magnetig.
    

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