Statistical properties of shock-accelerated ions in the outer heliosphere

Abstract

view Abstract Citations (7) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Statistical Properties of Shock-accelerated Ions in the Outer Heliosphere Lanzeroti, L. J. ; Thomson, D. J. ; Maclennan, C. G. ; Gold, R. E. ; Decker, R. E. ; Krimigis, S. M. Abstract Reported here are statistical studied of interplanetary protons (about 0.5-1.5 MeV) as measured by the Voyager 2 spacecraft in the outer heliosphere between about 1 and 22 AU. The acceleration processes which produce the fluctuations in intensity of the protons throughout the interval studied are caused by solar flare-generated shock waves and corotating shock structures in the solar wind. It is found that the proton count rates can be represented by a lognormal distribution, independent of the phase of the solar cycle in which the measurements were made. Power spectra of the logarithm of the counts show that for frequencies in the range of about 0.02-0.5 cycles per day, the spectra can be characterized as about f exp -2. At lower frequencies, the spectra turn over and flatten. Over the entire frequency range studied, about 0.002-0.5 cycles per day, the spectra are therefore nonfractal. The rollover in the spectra at about 100 days probably represents the reorganization time for solar wind streams within the coronal source at the sun. Publication: The Astrophysical Journal Pub Date: October 1991 DOI: 10.1086/186181 Bibcode: 1991ApJ...380L..93L Keywords: Cosmic Rays; Heliosphere; Ion Beams; Particle Acceleration; Statistical Analysis; Interplanetary Magnetic Fields; Power Spectra; Shock Wave Propagation; Solar Wind; Voyager 2 Spacecraft; Space Radiation; COSMIC RAYS: GENERAL; INTERPLANETARY MEDIUM; SUN: PARTICLE EMISSION full text sources ADS |