DISTRIBUTION OF DENSITY IN A PLANETARY EXOSPHERE. PART II

Journal Article · Wed Feb 01 04:00:00 EST 1961 · Physics of Fluids (U.S.)

DOI:https://doi.org/10.1063/1.1724432· OSTI ID:4095471

Opik, E J; Singer, S F

In an isolated neutral exosphere three componentsocan be distinguished: elliptic-ballistic, hyperbolic-ballistic, and bound-elliptic. The second component forms the escape flux, which cannot be defined simply. The velocity distribution of all components was calculated as a function of altitude in the exosphere. From this, the importance of the bound orbits can be assessed. Even with the bound orbits completely filled, according to detailed balancing, the velocity distributicn is non-Maxwellian; hence the barometric formula cannot be applied to determine the distribution of density. The absence of a Maxwellian distribution is shown to exist at all levels above the reference level (base of the exosphere), and the effective kinetic temperature of the gas is shown to decrease with altitude. The "base of the exosphere" forms the dividing level between the barosphere and exosphere; its conventional definition was reexamined, and it is redefined to correspond to the level from which one-half of the escaping molecules may escape without suffering any collisions. Numerical results for all components vs. altitude are given for neutral hydrogen and oxygen, applicable to the terrestrial exosphere. The contribution of bound orbits was estimated and shown to be minor at all levels. Bound orbits may be important for the exospheres of the outer planets. The interplanetary gas may be considered as an extension of the solar atmosphere; however, caution must be exercised in treating it as an exosphere. (auth)

• Research Organization: Univ. of Maryland, College Park
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-009635
• OSTI ID: 4095471
• Journal Information: Physics of Fluids (U.S.), Journal Name: Physics of Fluids (U.S.) Vol. Vol: 4; ISSN PFLDA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ASTROPHYSICS
ATMOSPHERE
COLLISIONS
DENSITY
DISTRIBUTION
EARTH
ENVIRONMENT
GASES
GEOPHYSICS
HYDROGEN
LEVELS
MAXWELL DISTRIBUTION
MOLECULES
NUMERICALS
ORBITS
OXYGEN
PARTICLES
PHYSICS
PLANETS
PRESSURE
SPACE
SUN
TEMPERATURE
VELOCITY