紫外光波段的太陽子群與電漿環

Sunspot Loops in Ultraviolet
影像提供 : TRACE Project, NASA

Explanation:
It was a quiet day on the Sun. The above image shows, however, that even during off days the Sun's surface is a busy place. Shown in ultraviolet light, the relatively cool dark regions have temperatures of thousands of degrees Celsius. Large sunspot group AR 9169 is visible as the bright area near the horizon. The bright glowing gas flowing around the sunspots has a temperature of over one million degrees Celsius. The reason for the high temperatures is unknown but thought to be related to the rapidly changing magnetic field loops that channel solar plasma. Sunspot group AR 9169 moved across the Sun during 2000 September and decayed in a few weeks.

說明:
對太陽來說這是相當寧靜的一天。不過上面影像顯示就是在休息時候，太陽表面還是一個很忙碌的地方。
這張紫外光波段影像較冷較暗的區域，溫度大約有攝氏數千度左右。 影像中間的明亮區域是編號AR 9169的大黑子群，黑子周圍環繞著光亮的熾熱氣體，氣體的溫度超過攝氏一百萬度。
為什麼這些氣體的溫度會這麼高呢？這仍然是個待解的謎團，不過原因可能和周圍這些引導太陽電漿的快速變化磁場環有關。 太陽黑子群AR 9169在2000年的9月活躍於太陽表面，持續了數週才消失。

資料來源：Scientific American
　　　　　Department of Physics, NCKU