Laboratory measurement of large‐amplitude whistler pulses generated by fast magnetic reconnection

Abstract

We present observations of large‐amplitude (δB/B∼ 0.01) oblique whistler wave pulses generated by a spontaneous, 3‐D localized magnetic reconnection event in the Caltech jet experiment. The wave pulses are measured more than 50 ion skin depths from the reconnection location by a tetrahedron array of three‐axis B‐dot probes that mimic the pyramid flight formations of the Cluster and Magnetospheric Multiscale Mission spacecraft. Measurements of background parameters, wave polarization, and wave dispersion confirm that the pulses are whistler modes. These results demonstrate that localized impulsive reconnection events can generate large‐amplitude, oblique whistler wave pulses that propagate far outside the reconnection region. This provides a new pathway for the generation of magnetospheric whistler pulses and may help explain relativistic particle acceleration in phenomena such as solar flares that incorporate 3‐D localized impulsive magnetic reconnection.

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