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dc.contributor.authorDesai, Mihir I.
dc.contributor.authorMason, Glenn M.
dc.contributor.authorDwyer, Joseph R.
dc.contributor.authorMazur, Joseph E.
dc.contributor.authorSmith, Charles W.
dc.contributor.authorSkoug, Ruth M.
dc.date.accessioned2017-02-17T18:06:10Z
dc.date.available2017-02-17T18:06:10Z
dc.date.issued2001-05-20
dc.identifier.citationDesai, M. I., Mason, G. M., Dwyer, J. R., Mazur, J. E., Smith, C. W., & Skoug, R. M. (2001). Acceleration of 3He nuclei at interplanetary shocks. Astrophysical Journal, 553(1 PART 2), L89-L92. doi:10.1086/320503en_US
dc.identifier.urihttp://hdl.handle.net/11141/1194
dc.description.abstracte 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 as measured in terms of the daily occurrence rates of sunspots and X-ray flares. The ³He enhancements at IP shocks cannot be attributed to a rigidity-dependent acceleration of solar wind ions and are better explained if the shocks accelerate ions from multiple sources, one being remnant impulsive solar flare material enriched in ³He ions. Our results also indicate that the contribution of impulsive flares to the seed population for IP shocks varies from event to event and that the interplanetary medium is being replenished with impulsive material more frequently during periods of increased solar activity.en_US
dc.language.isoen_USen_US
dc.rightsThis published article is made available in accordance with the publisher’s policy. It may be subject to U.S. copyright law.en_US
dc.rights.urihttps://aas.org/publications/aas-copyright-policyen_US
dc.titleAcceleration of ³He nuclei at interplanetary shocksen_US
dc.typeArticleen_US
dc.identifier.doi10.1086/320503


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