EVAPORATION OF THE SOLAR CORONA INTO INTERPLANETARY SPACE.
Abstract
A simple kinetic theory model of the interplanetary gaseous medium based on the evaporation of particles from the solar coronal exosphere is considered, using Jeans' equation for the escape of gases from planetary atmospheres. The exosphere is fixed in the corona at a level (four times the solar radius) where the mean free path is comparable with the scale height. Equality of flux for the protons and electrons at the exosphere is assumed, so that the sun may not build up an inordinately high charge. Ingham's density value is used at the exosphere, where the temperature is assumed to be 1,000,000 degrees K. The electric potential at the exosphere is found to be about 488 volts and is almost equal and opposite to the gravitational potential for the protons so that the protons are virtually weightless. Computed particle density values are in good agreement with the observational data of van de Hulst, Vitkevitch and Slee. The theoretical proton (particle) flux and velocity near the earth are, respectively, 1.47 x 10 to the 8th power 1/sq-cm sec, and 147 km/s. These values are in order-of-magnitude agreement with the Lunik II, Explorer X, and Mariner II data. The order-of-magnitude agreement does not depend critically on the value at the exospheric level or on making the protons actually weightless. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1965
- Accession Number
- AD0616775
Entities
People
- Hari K. Sen
Organizations
- Air Force Cambridge Research Laboratories