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Hiss-triggered chorus emissions at Indian stations

2004; Elsevier BV; Volume: 66; Issue: 12 Linguagem: Inglês

10.1016/j.jastp.2004.03.013

1879-1824

Rajesh Singh, R. P. Patel,

Earthquake Detection and Analysis

Abstract Some examples of chorus emissions emanating from the upper edge of the underlying hiss events recorded at the Indian Antarctic Station Maitri (geomag. lat.=62°S, long. 57.2° E, L=4.5) and low-latitude station Gulmarg (geomag. lat.=24°26′N, long. 147°09′E) are reported, in which intensity seems to decrease with increase in frequency and also it varies from event to event. It is proposed that resonance interaction of energetic electrons with wavelets present in the upper edge of hiss elements propagating in whistler mode under suitable condition behaves as a backward wave oscillator and generates chorus emissions. The minimum and the maximum value of interaction length, beam modulation period and temporal evolution of emitted wave frequency have been evaluated. Modulation period has been used to explain the periodicity in the recorded events and the temporal evolution of wave frequency has been used to explain the shape of dynamic spectrum of hiss-triggered emissions.