Physical Sciences and Mathematics Commons^™

Acceleration Of ³He Nuclei At Interplanetary Shocks, Mihir I. Desai, Glenn M. Mason, Joseph R. Dwyer, Joseph E. Mazur, Charles W. Smith, Ruth M. Skoug

Aerospace, Physics, and Space Science Faculty Publications

We have surveyed the 0.5-2.0 MeV nucleonˉ¹ ion composition of 56 interplanetary (IP) shocks observed with the Ultra - Low-Energy Isotope Spectrometer on board the Advanced Composition Explorer from 1997 October 1 through 2000 November 30. Our results show the first ever measurement (25 cases) of ³He ions being accelerated at IP shocks. The ³He/⁴He ratio at the 25 shocks exhibited a wide range of values between 0.0014 and 0.24; the ratios were enhanced between factors of ∼3 and 600 over the solar wind value. During the survey period, the occurrence probability of ³He-rich shocks increased with rising solar activity …