The field and plasma configuration of a filament overlying a solar bipolar magnetic region
Abstract
This paper presents an analytic model for a finite-size straight filament suspended horizontally in a steady state over a bipolar magnetic region. The equations of magnetostatic equilibrium are integrated exactly. The solution obtained illustrates the roles played by the electric current, magnetic field, pressure, and plasma weight in the balance of force everywhere in space. A specific example of a filament of diameter 50,000 km, with a density two orders of magnitude over the corona and supported by a magnetic field of about 4 gauss is included. The filament temperature can take values ranging from a small fraction to a few times the coronal temperature, depending on the internal electric current of the filament. To produce a cool filament, such as the quiescent prominence, the solution is required to have an internal field with a strong component along the filament, giving rise to helical structures. A hot filament such as the X-ray coronal loop can be produced as a twisted magnetic flux tube embedded in a strong background field aligned parallel to the filament and having lower density and temperature. The basic steps of construction can be used to develop models more realistic than the ones presented for their analytic simplicity.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1981
- DOI:
- 10.1086/158954
- Bibcode:
- 1981ApJ...246..538L
- Keywords:
-
- Magnetic Field Configurations;
- Magnetohydrodynamics;
- Solar Corona;
- Solar Magnetic Field;
- Solar Prominences;
- Bipolarity;
- Coronal Loops;
- Electric Current;
- Magnetostatics;
- Plasma Cooling;
- Plasma Equilibrium;
- Plasma Heating;
- Solar Temperature;
- Temperature Profiles;
- Solar Physics