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Observations of geomagnetic cutoff variations during solar energetic particle events and implications for the radiation environment at the Space Station

Leske, R. A. and Mewaldt, R. A. and Stone, E. C. and von Rosenvinge, T. T. (2001) Observations of geomagnetic cutoff variations during solar energetic particle events and implications for the radiation environment at the Space Station. Journal of Geophysical Research A, 106 (A12). pp. 30011-30022. ISSN 0148-0227. https://resolver.caltech.edu/CaltechAUTHORS:20150306-101831498

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Abstract

Data from the polar-orbiting Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite have been used to measure the location of the geomagnetic cutoff for low-energy protons and alpha particles during several large solar energetic particle events from mid-1992 to late 1998. When fluxes are sufficiently high, the cutoff latitude can be measured up to four times per orbit, allowing the variability of the cutoff to be observed on relatively short timescales. We find significant changes in the cutoff location, often by more than 5° in less than 1 day, and these changes are well correlated with geomagnetic activity as measured by either Dst or Kp. Spacecraft in intermediate-inclination orbits such as the International Space Station (ISS) graze the geomagnetic polar cap at certain longitudes each day. Calculations show that a 5° suppression in the average geomagnetic cutoff increases by more than a factor of 2.5 the time that the ISS spends in the polar cap exposed to energetic particles. Since the Station is only vulnerable at certain longitudes, however, real-time monitoring of the cutoff location from a polar-orbiting spacecraft could be used to provide advance notice of the polar cap location and conditions, sometimes hours before the Space Station itself reaches high magnetic latitudes.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2000JA000212 DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/2000JA000212/abstractPublisherArticle
ORCID:
AuthorORCID
Mewaldt, R. A.0000-0003-2178-9111
Additional Information:© 2001 by the American Geophysical Union. Paper number 2000JA000212. Received June 30, 2000; revised August 25, 2000; accepted September 14, 2000. This work was supported by NASA under contract NAS5-30704 and grant NAGW-1919. GOES data, Dst, and Kp indices were obtained from the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, through the Space Environment Center and the National Geophysical Data Center. Janet G. Luhmann thanks Henry Garrett and Ron Turner for their assistance in evaluating this paper.
Group:Space Radiation Laboratory
Funders:
Funding AgencyGrant Number
NASANAS5-30704
NASANAGW-1919
National Oceanic and Atmospheric Administration (NOAA) UNSPECIFIED
National Geophysical Data CenterUNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2003-28
Issue or Number:A12
Record Number:CaltechAUTHORS:20150306-101831498
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150306-101831498
Official Citation:Leske, R. A., R. A. Mewaldt, E. C. Stone, and T. T. vonRosenvinge (2001), Observations of geomagnetic cutoff variations during solar energetic particle events and implications for the radiation environment at the Space Station, J. Geophys. Res., 106(A12), 30011–30022, doi:10.1029/2000JA000212
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:55589
Collection:CaltechAUTHORS
Deposited By: Deborah Miles
Deposited On:07 Mar 2015 00:20
Last Modified:22 Nov 2019 09:58

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