Visible around the darkened Sun during a total solar eclipse, the corona is the luminous envelope surrounding the Sun outside the chromosphere—the upper, rarefied solar atmosphere. The basic structure of the corona is formed by coronal loops, which result from the twisted solar magnetic flux within the Sun and exhibit a wide range of temperatures. How are these massive coronal loops related to the coronal heating problem—the mystery of why the Sun’s corona is far hotter than its surface? Discuss
Source: The Free Dictionary