Interim Report on the Power Law Index of Interplanetary Suprathermal Ion Spectra

Journal Article · Thu Dec 30 00:00:00 EST 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3529991· OSTI ID:21506831

Hill, M E ^[1]; Hamilton, D C ^[2]

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1. Johns Hopkins Applied Physics Laboratory, Laurel, Maryland 20723 (United States)
2. University of Maryland College Park, Maryland 20742 (United States)

There is a continuing debate about the applicability of the theory presented by Fisk and Gloeckler (FG) regarding the formation of suprathermal ion tails in phase space density vs. velocity spectra; in the solar wind frame the FG theory predicts a power law index of-5 (which is equivalent to a differential intensity vs. energy index of-1.5). There has also been uncertainty and perhaps misunderstanding regarding the extent to which such spectra are actually observed; i.e., is there really a significant preference for the -5 index? Here we report the results of an interim technique we use to analyze {approx}1-100 keV/nucleon interplanetary suprathermal H{sup +}, He{sup +}, and He{sup ++}, spectra measured at the Cassini spacecraft by the Charge Energy Mass Spectrometer (CHEMS) instrument of the Magnetospheric Imaging Instrument (MIMI) suite during the cruise to Saturn. We analyzed 18 active periods and report a mean index in the solar wind frame of 4.9{+-}0.4 for protons, 5.2{+-}0.5 for He{sup +}, and 4.7{+-}0.2 for alpha particles. MIMI/CHEMS offers much needed independent observations of heliospheric ions in the suprathermal energy range.

• OSTI ID: 21506831
• Journal Information: AIP Conference Proceedings, Vol. 1302, Issue 1; Conference: 9. annual international astrophysics conference, Maui, HI (United States), 14-19 Mar 2010; Other Information: DOI: 10.1063/1.3529991; (c) 2010 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ALPHA PARTICLES
CHARGED PARTICLE DETECTION
DENSITY
EARTH MAGNETOSPHERE
HELIUM IONS
HYDROGEN IONS 1 PLUS
KEV RANGE
MASS SPECTROMETERS
PHASE SPACE
SATURN PLANET
SOLAR WIND
SPECTRA
VELOCITY
CATIONS
CHARGED PARTICLES
DETECTION
EARTH ATMOSPHERE
ENERGY RANGE
HYDROGEN IONS
IONIZING RADIATIONS
IONS
MATHEMATICAL SPACE
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
PLANETS
RADIATION DETECTION
RADIATIONS
SOLAR ACTIVITY
SPACE
SPECTROMETERS
STELLAR ACTIVITY
STELLAR WINDS