Continuum radiation in planetary magnetospheres

Conference · Sun Dec 01 04:00:00 EST 1991

OSTI ID:5399383

Kurth, W S

With the completion of the Voyager tour of the outer planets, radio and plasma wave instruments have executed the first survey of the wave spectra of Earth, Jupiter, Saturn, Uranus, and Neptune. One of the most notable conclusions of this survey is that there is a great deal of qualitative similarity in both the plasma wave and radio wave spectra from one magnetosphere to the next. In particular, in spite of detailed differences, most of the radio emissions at each of the planets have been tentatively classified into two primary categories. First, the most intense emissions are generally associated with the cyclotron maser instability. Second, a class of weaker emissions can be found at each of the magnetospheres which appears to be the result of conversion from intense electrostatic emissions at the upper hybrid resonance frequency into (primarily) ordinary mode radio emission. It is this second category, often referred to as nonthermal continuum radiation, which we will discuss in this review. We review the characteristics of the continuum spectrum at each of the planets, discuss the source region and direct observations of the generation of the emissions where available, and briefly describe the theories for the generation of the emissions. Over the past few years evidence has increased that the linear mode conversion of electrostatic waves into the ordinary mode can account for at least some of the continuum radiation observed. There is no definitive evidence which precludes the possibility that a nonlinear mechanism may also be important.

• Research Organization: Iowa Univ., Iowa City, IA (United States)
• OSTI ID: 5399383
• Report Number(s): N-92-19056; NASA-CR--189903; NAS--1.26:189903; U-OF-IOWA--91-29; CONF-9109372--; CNN: JPL-957723; JPL-959193
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLIFIERS
ATMOSPHERES
BREMSSTRAHLUNG
CYCLOTRON RADIATION
EARTH PLANET
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EMISSION SPECTRA
EQUIPMENT
JUPITER PLANET
MASERS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
NEPTUNE PLANET
NONLINEAR PROBLEMS
PLANETARY ATMOSPHERES
PLANETARY MAGNETOSPHERES
PLANETS
PLASMA WAVES
RADIATIONS
RADIOWAVE RADIATION
SATURN PLANET
SPACE VEHICLES
SPECTRA
URANUS PLANET
VEHICLES
VOYAGER SPACE PROBES