Fig6_7 Magnetic and gas pressure

Fig6_7 Magnetic and gas pressure

Fig. 6.7 . The ratio of gas to magnetic pressure, denoted by the symbol b, plotted as a function of height above the photosphere. The magnetic pressure is greater than the gas pressure in the low corona, where b is less than one, and magnetic fields dictate the structure of the corona. Further out, the gas pressure can exceed the magnetic pressure, which permits the solar wind to carry the Sunís magnetic field into interplanetary space. In the photosphere, below the corona and chromosphere, the gas pressure also exceeds the magnetic pressure, and the moving gas carries the magnetic fields around. [Adapted from G. Allen Gary, Plasma beta above a solar active region: Rethinking the paradigm, Solar Physics 203, 71-86 (2001).]

Copyright 2010, Professor Kenneth R. Lang, Tufts University