Plasma Composition in Jupiter's Magnetosphere: Initial Results from the Solar Wind Ion Composition Spectrometer

Area of Science:

• Planetary Science
• Space Physics
• Plasma Physics

Background:

• Jupiter's magnetosphere is a complex environment containing plasma from various sources.
• Understanding the ion composition is crucial for comprehending magnetospheric processes.

Purpose of the Study:

• To investigate the ion composition within Jupiter's magnetosphere.
• To identify the sources and distribution of plasma in the Jovian environment.

Main Methods:

• In-situ measurements using the Solar Wind Ion Composition Spectrometer (SWICS) on the Ulysses spacecraft.
• Analysis of ion species, charge states, and plasma temperatures.

Main Results:

• A hot, tenuous plasma was observed throughout Jupiter's outer and middle magnetosphere.
• Oxygen and sulfur ions from Jupiter's moon Io were the primary contributors to the plasma mass density, even at high latitudes.
• Two distinct thermal plasma components were identified in certain regions.
• Solar wind particles were detected across all investigated regions.
• Ions originating from Jupiter's ionosphere were abundant, particularly in the high-latitude dusk region.

Conclusions:

• The volcanic moon Io is a significant source of plasma in Jupiter's magnetosphere.
• Jupiter's magnetosphere is populated by a mix of solar wind, ionospheric, and satellite-derived ions.
• The observed plasma distribution provides insights into magnetospheric dynamics and transport processes.