# Accession Number:

## ADA169745

# Title:

## An Analytic Theory for Trajectories and Current to a Cylinder in a Flowing Magnetoplasma.

# Descriptive Note:

## Environmental research papers,

# Corporate Author:

## AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

# Personal Author(s):

# Report Date:

## 1985-11-22

# Pagination or Media Count:

## 29.0

# Abstract:

Two dimensional guiding center theory for a body in a flowing magnetoplasma leads to the electric potential satisfying Laplaces equation outside of the body, one or two forbidden regions, and the inner part of the wake. It is applied to a conducting cylinder larger than the shuttle, of circular cross section, with radius much less than the length, aligned with the magnetic field, which is perpendicular to the flow vector. Ion and electron trajectories and current to the cylinder are calculated. The effects of collisions, waves, and turbulence are neglected, as is the charge in the forbidden regions and wake. Because of this, the potential and trajectories of the nonimpacting particles are symmetric in the ram and wake. Therefore, the theory results in no particles hitting the wake side and no ion focusing. The steady state potentials result in -0.26 and -0.61 V for cylinder radii of 25 and 250 m, respectively. The result of calculating the charging time constant due to capacitance is the order of 1 ns, which is negligible compared to the transit time. Therefore, the charging time is determined by the transit time and Current to a Cylinder in a Flowing Magnetoplasma. Keywords Analytic theory Cylindrical spacecraft Two dimensional theory Guiding center to previous page and not by capacitance.

# Descriptors:

# Subject Categories:

- Atmospheric Physics
- Electricity and Magnetism
- Plasma Physics and Magnetohydrodynamics