PAMELA's measurements of geomagnetic cutoff variations during the 14 December 2006 storm

Abstract

Data from the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) satellite experiment were used to measure the geomagnetic cutoff for high-energy (>80 MeV) protons during the 14 December 2006 geomagnetic storm. The variations of the cutoff latitude as a function of rigidity were studied on relatively short timescales, corresponding to spacecraft orbital periods (94 min). Estimated cutoff values were compared with those obtained by means of a trajectory tracing approach based on a dynamical empirical modeling of the Earth's magnetosphere. We found significant variations in the cutoff latitude, with a maximum suppression of about 7 deg at lowest rigidities during the main phase of the storm. The observed reduction in the geomagnetic shielding and its temporal evolution were related to the changes in the magnetospheric configuration, investigating the role of interplanetary magnetic field, solar wind and geomagnetic parameters. PAMELA's results represent the first direct measurement of geomagnetic cutoffs for protons with kinetic energies in the sub-GeV and GeV region.

arXiv comment26 pages, 6 figures and 1 table. Accepted for publication in Space Weather

References in corpus (9)

• PAMELA - A Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics
• Time dependence of the proton flux measured by PAMELA during the July 2006 - December 2009 solar minimum
• Time dependence of the e^- flux measured by PAMELA during the July 2006 - December 2009 solar minimum
• Observations of the December 13 and 14, 2006, Solar Particle Events in the 80 MeV/n - 3 GeV/n range from space with PAMELA detector
• Elliptical model of cutoff boundaries for the solar energetic particles measured by POES satellites in December 2006
• PAMELA's Measurements of Magnetospheric Effects on High Energy Solar Particles
• Trapped proton fluxes at low Earth orbits measured by the PAMELA experiment
• PAMELA's measurements of geomagnetically trapped and albedo protons
• PAMELA's measurements of geomagnetic cutoff variations during solar energetic particle events

Cited by in corpus (4)

• Solar energetic particle events observed by the PAMELA mission
• Calibration of the GOES-13/15 high energy proton detectors based on the PAMELA solar energetic particle observations
• Evidence of energy and charge sign dependence of the recovery time for the December 2006 Forbush event measured by the PAMELA experiment
• Geomagnetically trapped, albedo and solar energetic particles: trajectory analysis and flux reconstruction with PAMELA