Effects of equatorially trapped ions on refilling of the plasmasphere

Journal Article · Sat Feb 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA01861· OSTI ID:5447914

Singh, Nagendra; Chan, C B ^[1]

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1. Univ. of Alabama, Huntsville (United States)

The observation of trapped ions in the equatorial region of the outer plasmaspheric flux tubes suggests interesting plasma processes, which can significantly affect the refilling of such tubes after geomagnetic storms. The trapped ions are created by perpendicular ion heating by wave-particle interactions. During the early stage of the refilling, the heated ions come from the field-aligned flows of thermal plasma from the conjugate ionospheres. If the heating is sufficiently strong, the mirror force on the heated ion decouples the interhemispheric plasma exchange, and each hemisphere refills with the plasma supplied by its own ionospheres. If the heating is sufficiently strong, the mirror force on the heated ion decouples the interhemispheric plasma exchange, and each hemisphere refills with the plasma supplied by its own ionosphere. The generation of the trapped ions and the refilling processes are modeled by solving time-dependent plasma transport equations. The refilling is found to occur in two stages. The first (initial) stage involves (1) development of supersonic flows from the conjugate ionospheres, (2) perpendicular ion heating at the equator, (3) retardation of the interhemispheric flow by the mirror force as the heated ions tend to flow downward from the equator, and (4) formation of shocks in the supersonic flows at the equator and their downward propagation to the conjugate ionospheres. This entire phase lasts only a few hours. Since shock formation in a hydrodynamic model is questionable, it is verified kinetically by means of a numerical simulation which shows that shocks form at the mirror points of the equatorially heated ions. The kinetic simulation deals with small-scale counterstreaming plasma expansion in a mirror type of magnetic field with minimum magnetic field at the center.

• OSTI ID: 5447914
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A2; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANISOTROPY
BARYONS
COMPUTERIZED SIMULATION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC FIELDS
ELEMENTARY PARTICLES
FERMIONS
FLUID FLOW
GEOMAGNETIC EQUATOR
HADRONS
HEATING
ION DRIFT
IONOSPHERE
MAGNETIC FLUX
MAGNETIC STORMS
MATHEMATICAL MODELS
NUCLEONS
PLANETARY IONOSPHERES
PLASMA DENSITY
PLASMASPHERE
PROTONS
SHOCK WAVES
SIMULATION
SUPERSONIC FLOW
TRAPPED PROTONS