Development and global oscillations of cometary ionospheres

Journal Article · Sun Feb 01 00:00:00 EST 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158673· OSTI ID:6195667

Houpis, H L.F.; Mendis, D A

Representing the cometary ionosphere by a single fluid model characterized by an average ionization time scale, we have studied both its development as a comet approaches the sun and its response to sudden changes in the solar wind conditions. Three different nuclear sizes, small average, and very large, as well as three different modes of energy addition to the atmosphere, adiabatic, isothermal, and suprathermal, are considered. The crucial parameter determining both the nature and the size of the ionosphere is the average ionization time scale within the ionosphere. We identify two different ionization time scales: one during ''quiet'' solar wind conditions when photoionization is the principal source of ionization there, and a secod, much shorter time scale, subsequent to the encounter by a comet of a solar wind high-speed stream, when a beam of energetic electrons discharged from the comet's tail into the ionosphere is the main ionizing agent.

• Research Organization: Univ. of California, San Diego, CA (United States)
• OSTI ID: 6195667
• Journal Information: Astrophys. J.; (United States), Vol. 243:3
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMETS
PLASMA
ADIABATIC PROCESSES
CONTINUITY EQUATIONS
EXPANSION
FLUID FLOW
HYDRODYNAMICS
IONIZATION
ISOTHERMAL PROCESSES
MAGNETIC FLUX
OSCILLATIONS
PHOTOIONIZATION
SHOCK WAVES
SOLAR WIND
DIFFERENTIAL EQUATIONS
EQUATIONS
FLUID MECHANICS
MECHANICS
PARTIAL DIFFERENTIAL EQUATIONS
SOLAR ACTIVITY
640107* - Astrophysics & Cosmology- Planetary Phenomena