# Accession Number:

## ADA155257

# Title:

## Ionospheric Electron Density Profile and Related Studies.

# Descriptive Note:

## Final rept. 1 Oct 80-15 Jul 84

# Corporate Author:

## BOSTON COLL CHESTNUT HILL MA SPACE DATA ANALYSIS LAB

# Personal Author(s):

# Report Date:

## 1984-08-15

# Pagination or Media Count:

## 74.0

# Abstract:

We have studied photo-ionization of the neutral gas by photons in the extreme ultraviolet EUV region of the solar spectrum along with the various particle-particle collisional processes that determine the energy dependence of the photo-electron flux. We have also studied the effects of plasma instabilities in determining the photoelectron energy spectrum in the 2-6 eV energy range. We describe a series of case studies, modeling the EDPElectron Density Profile using first-principle calculations and comparing the results to a variety of direct measurements. For cases in which simultaneous airflow emission measurements are available, we evaluate the emissions predicted by our model EDP and compare with the observed emissions. We have addressed the problem of specifying the flux incident on the atmosphere with a calculation of the magnetospheric loss-cone population resulting from pitch-angle diffusion. In an effort to describe the phenomena of ion conics, we have also studied both the means by which turbulence can be caused by precipitating electrons and the way in which the turbulence can accelerate ionospheric ions, using particle plasma simulation techniques. A simplified analysis shows no dependence upon beam current for the spherical geometry and a weak dependence for the cylindrical case. Keywords Photoeltectron energy spectrum Plasma instabilities lower hybrid frequency upper hybrid instability electronic cyclogron instability linear plasma theory electron density ion acceleration ion conics airglow emission probe potential spacecraft charging loss cone particle precipitation curve-particle interaction Monte Carlo model plasma simulation beam current ion space charge.

# Descriptors:

- *ELECTRON DENSITY
- *EMISSION SPECTRA
- *AIRGLOW
- *MAGNETOSPHERE
- SIMULATION
- IONOSPHERE
- IONS
- MEASUREMENT
- PROBES
- STABILITY
- SPACECRAFT
- FLUX(RATE)
- PLASMAS(PHYSICS)
- THEORY
- TURBULENCE
- MONTE CARLO METHOD
- POPULATION
- ELECTRONS
- ELECTRON BEAMS
- PRECIPITATION
- PARTICLES
- PROFILES
- LINEARITY
- LOSSES
- SYNCHRONISM
- ELECTRIC CURRENT
- LOW STRENGTH
- SPACE CHARGE
- PHOTOELECTRONS
- ELECTRIC CHARGE
- CYCLOTRONS

# Subject Categories:

- Atmospheric Physics