Joule heating of the Jovian ionosphere by corotation enforcement currents

Journal Article · Sun Nov 01 04:00:00 EST 1981 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA086iA12p09945· OSTI ID:6020978

Nishida, A; Watanabe, Y

Heat is deposited to the Jovian ionosphere in the course of enforcement of corotation to the outer magnetosphere. The Joule heating rate is estimated for several possible causes of departure from the corotation by making use of a simple model of the magnetodisc. Following compression or expansion of the magnetosphere, the magnetospheric plasma superrotates or subrotates in consequence of conservation of the angular momentum, and thermal energy is deposited in the ionosphere at a rate of the order of 10/sup 12/ W for about 10/sup 5/ s while rotational speed is adjusted toward the corotation with the planet. Outward diffisuion of the Iogenic plasma at a rate of 10/sup 29/ amu/s also causes ionospheric heating at a rate of 10/sup 13/ W as the ionosphere acts to drive the plasma toward the corotation. Day-night asymmetry in trajectory of rotational motion of plasma, owing to asymmetry in configuration of the magnetosphere, is also likely to produce energy dissipation of a similar magnitude as the rotational speed is adjusted continually. Thus the corotation enforcement current deposits as much heat as the dynamo current from Io and plays an important part in energetics and dynamics of the Jovian magnetosphere. The heating rate per unit area of the high-latitude ionosphere is more than approx.10 erg/cm/sup 2/ s, namely, orders of magnitude greater than the rate of the energy supply by the solar UV radiation. These numbers depend on the adopted height-integrated conductivity of 0.1 mho of the Jovian ionosphere.

• Research Organization: The Institute of Space and Astronautical Science, Meguro-ku, Tokyo 153, Japan
• OSTI ID: 6020978
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 86:A12; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DAILY VARIATIONS
EARTH ATMOSPHERE
ELECTRIC HEATING
ENERGY TRANSFER
EXPANSION
HEATING
JOULE HEATING
JUPITER PLANET
MAGNETOSPHERE
MOTION
PLANETARY IONOSPHERES
PLANETS
PLASMA EXPANSION
PLASMA HEATING
RESISTANCE HEATING
ROTATION
VARIATIONS