The gross energy balance of solar active regions

According to Parker's earlier articles in this journal the photospheric temperature is lower in sunspots than elsewhere because of increased outflow of mechanical energy, rather than inhibited inflow from the convective zone. In this case the atmosphere above the spot group receives an excess supply of energy that must equal the deficiency in radiative power output of the spot group compared with the normal photosphere. The extra power supplied to the atmosphere was then assumed to be lost by radiation. On 26 November 1973 the active region McMath 12628 was studied with sufficient precision to test for this equality. It is shown that the atmosphere did not radiate and almost certainly did not receive, more than a very small part of the missing flux of the spot group. This result is an important constraint on the plausible theories of sunspot formation.