Solar prominence magnetic configurations derived numerically from convection

Abstract

The solar convection zone may be a mechanism for generating the magnetic elds in the corona that create and thermally insulate quiescent prominences. This connection is examined here by numerically solving a diusion equation with convection (below the photosphere) matched to Laplace's equation (modeling the current free corona above the photosphere). The types of elds formed resemble both Kippenhahn-Schluter and Kuperus- Raadu congurations with feet that drop into supergranule boundaries. 1. Prominence models The of the Sun, from the base of the chro- mosphere through the corona, is structured by magnetic elds. Presumably generated in the convection zone these elds break through the photosphere stimulating a vari- ety of plasma formations, from small brils that outline convection cells to gigantic solar quiescent prominences that tower above the surface. In this paper we attempt a connection between the ejection of magnetism by con- vection cells to the structure of these prominences. The term \prominence can refer to any formation of cool dense material in the corona but a quiescent prominence is the largest and most stable of these formations. First ob- served during eclipses in the middle ages, they have been described as both \clouds in the lunar atmosphere and \mountains on the Sun. With the development of photo- graphic and spectrographic methods they are now known to be glowing masses of gas suspended in the Sun's atmo- sphere by magnetic elds. The rst mathematical models were developed by Menzel (1951) and Dungey (1953). These early mod- els proved unrealistic. For example, Menzel's model pre- dicted prominences that were as wide as they were tall. Better models were developed by Kippenhahn & Shluter (KS) (1957) and Kuperus & Raduu (KR) (1974). These models have better withstood the test of time and are the basis for much work on quiescent promi- nences. For detailed accounts of the history and physics of prominences see the books \Solar Prominences by Tandberg-Hanssen (1974) and \Dynamics and Structure of Quiescent Solar Prominences edited by Priest (1989).