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Kelvin-Helmholtz(K-H) waves are formed from the triggering of the K-H instability on the magnetopause,which is a candidate mechanism for solar wind entry into the magnetosphere,especially under northward interplanetary magnetic field conditions.In this study,a K-H wave event was identified from the observation of probe B of the Time History of Events and Macroscale Interactions during Substorms(THEMIS) mission on 15 May 2008.A new method to determine the wave parameters of the K-H waves in single-spacecraft observations is proposed.The dominant wave period is determined by three kinds of spectrograms for three key parameters,namely the ion density,the ion temperature,and the z component of magnetic field.The phase velocity is estimated by calculating the center-of-mass velocity of the detected K-H vortex region.This approximation is validated by comparison with other alternative methods.The method to determine the wave parameters is a first step to further study K-H wave properties and their relationship with interplanetary conditions.
Kelvin-Helmholtz (KH) waves are formed from the triggering of the KH instability on the magnetopause, which is a candidate mechanism for solar wind entry into the magnetosphere, especially under northward interplanetary magnetic field conditions. In this study, a KH wave event was identified from the observation of probe B of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission on 15 May 2008. A new method to determine the wave parameters of the KH waves in single-spacecraft observations is proposed. The dominant wave period is determined by three kinds of spectrograms for three key parameters, namely the ion density, the ion temperature, and the z component of magnetic field. the phase velocity is estimated by calculating the center-of-mass velocity of the detected KH vortex region .This approximation is validated by comparison with other alternative methods. The method to determine the wave parameters is a first step to further study KH wave properties and their relationship with interplanetary conditions.