HR: 0830h
AN: SM51B-0529    [PDF]
TI: Automatic Identification of ULF Waves in Triaxial Magnetic Records
AU: * Chi, P J
EM: pchi@igpp.ucla.edu
AF: UCLA Institute of Geophysics and Planetary Physics, Box 951567, Los Angeles, CA 90095-1567 United States
AU: Russell, C T
EM: ctrussel@igpp.ucla.edu
AF: UCLA Institute of Geophysics and Planetary Physics, Box 951567, Los Angeles, CA 90095-1567 United States
AU: Higuchi, T
EM: higuchi@ism.ac.jp
AF: Institute of Statistical Mathematics, 4-6-7, Minami-Azabu, Minato-ku, Tokyo, 106-8569 Japan
AB: Existing satellite magnetometer data contain numerous ULF wave events. Our complete understanding of these waves requires studying their statistical properties, but most studies rely on manual selection of wave events, which invites bias in the selected events. In addition, manual selection of wave events is extremely time consuming and cannot cope with the expected rapid increase in data collected by the multi-satellite missions in the next decade. This study develops the methodology as well as a computer algorithm for automatic identification of ULF waves in vector magnetic field data. We combine modern time-frequency analysis with statistical tests of spectral peaks in the procedure, which also includes cross correlation and polarization properties. Initial tests on ISEE and Polar magnetometer data show satisfactory results in identifying ULF wave events. Our analysis is also able to reveal delicate details in ULF wave data, such as the drift of field line resonance frequency as the spacecraft moves across $L$-shells as well as the slight frequency increase within a packet of pearl pulsations. The developed procedure can be used to efficiently establish a catalog of ULF wave events for statistical analysis on the implication of source mechanisms of these waves and on their role in radiation belt and ring current dynamics.
DE: 2752 MHD waves and instabilities
DE: 2772 Plasma waves and instabilities
DE: 2794 Instruments and techniques
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting