Fig. 4: EBWs observed near EDR.
From: Electron Bernstein waves driven by electron crescents near the electron diffusion region
a B. b Perpendicular and parallel components of the high-frequency E with \(f\, > \,\)50 Hz. (c) E\(\times\)B/B\(^{2}\) (lines) and 30-ms resolution V\(_{{\rm{e}},\perp }\) (dots). d Power spectrogram of E\(_{\perp }\). e Power spectrogram of B. The electron cyclotron harmonic frequencies are plotted in (d, e). The yellow-shaded region from 15:03:32.037 to 15:03:32.054 UTC highlights the E fluctuations with amplitudes larger than E\(_{{\rm{peak}}}\)/\({{{e}}}^{2}\), where E\(_{{\rm{peak}}}\) is the peak of the fluctuating E, and e \(\, \sim\, 2.718\) is the Euler identity. f Power spectrum of E\(_{\perp }\) within the yellow-shaded region. The average \({f}_{{\rm{ce}}}\) and the harmonic frequencies are over-plotted. g, h Hodograms of E\(_{\max }\) versus E\(_{{\rm{int}}}\), and E\(_{\max }\) versus E\(_{\min }\). The red line in (h) denotes the B direction. During the EBWs observations, the electron plasma frequency \({f}_{{\rm{pe}}}\, \sim\,\) 32.9 kHz is well above the electron cyclotron frequency \({f}_{{\rm{ce}}}\, \sim\,\) 860 Hz.
