Waves in the proton cyclotron frequency range in the CME observed by wind on August 7–8, 1996: theory and data

• Published in: Advances in Space Research Vol. 28; no. 5; pp. 747 - 752
• Main Authors: Dasso, S., Farrugia, C.J., Gratton, F.T., Lepping, R.P., Ogilvie, K.W., Fitzenreiter, R.J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Elsevier Ltd 01.01.2001
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/S0273-1177(01)00526-9

As first discussed by Farrugia et al. ( J. Geophys. Res., 103, 6543, 1998), coronal mass ejections (CMEs) may support the excitation of electromagnetic ion cyclotron waves (EICWs). The proton plasma beta, and the electron temperature and anisotropy in the front region (∼5 hours, translating to ∼6×10 6 km) of the CME observed by WIND on August 7–8, 1996 favor this possible excitation. Supplementing these measured parameters by other data taken from a survey of CME properties observed by the ISEE 3 spacecraft (Gosling et al., J. Geophys. Res., 92, 8519, 1987), we solve the EICW dispersion relation numerically. We find short e-folding times of EICWs, of the order of 5 min, i.e., much less than the typical evolution time of these ejecta. We suggest that high resolution data will show enhanced power in the 0.5 Hz range.