FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-19/04

Title and Subtitle: CARI-7 Documentation: Geomagnetic Cutoff Rigidity Calculations and Tables for 1965-2010

Report Date: July 2020

Authors: Copeland K

Abstract: To varying degrees, Earth's geomagnetic field protects the volume within its influence from energetic ions present in galactic and solar cosmic radiation. The accurate calculation of galactic and solar cosmic radiation dose rates and other related quantities in near-Earth space and within Earth's atmosphere requires knowledge of the influence of the geomagnetic field on these incoming energetic ions.

CARI (Civil Aviation Research Institute [this is the acronym for a previous name of what is now the Civil Aerospace Medical Institute, or CAMI]) software for calculating doses of ionizing radiation in the atmosphere from cosmic radiation has been in development since the late 1980s.

Similar to previous versions of CARI, the approach used by CARI-7 and CARI-7A to incorporate geomagnetic shielding relies on precalculated tables of effective vertical cutoff rigidities. Unlike previous versions, CARI-7A offers multiple options for handling these data. This report presents the geomagnetic shielding algorithms and data used by CARI-7 and -7A.

Key Words: Ionizing Radiation, Cosmic Radiation, Space Weather, Geomagnetism, CARI-7, CARI-7A

No. of Pages: 458