Ionization state of the solar wind

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6183529

Owocki, S P

The solar wind ionization state is frozen within a few solar radii of the photosphere, and measurements of the ions at 1 a.u. can therefore potentially yield information about conditions at the base of the coronal expansion. If ions are assumed to flow at a steady, common bulk speed in a plasma with a Maxwellian electron distribution, the interplanetary ionization state is characteristic of the electron temperature in the coronal freezing-in region. In this thesis, the effect of relaxing one or more of these assumptions is examined. The effects of intrinsic time variations (e.g. as in a coronal transient) in a uniform ion flow can be best understood through a Lagrangian approach of following individual fluid parcels; for example, in coronal outflow undergoing a strong shock, only fluid parcels shocked at or below the ambient freezing-in radius have their ionization state modified by the shock, and time-dependent ionization effects for the transition between two steady flows are thus likely to be limited to a narrow range of gas parcels which are shocked in the low corona and pass a fixed interplanetary observer in a few tens-of-minutes. It was also found that differential flow of the ions in the freezing-in region can exert a strong influence on the relative abundance of various ionization stages in the solar wind, and so independent knowledge of ion flow speeds at the base will be needed if coronal temperatures are to be accurately inferred from solar wind ionization state measurements.

• Research Organization: Colorado Univ., Boulder (USA)
• OSTI ID: 6183529
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOLTZMANN STATISTICS
CHARGED PARTICLES
ELECTRON TEMPERATURE
FLUID FLOW
INTERPLANETARY SPACE
IONIZATION
IONS
SOLAR ACTIVITY
SOLAR WIND
SPACE
VELOCITY