A generation mechanism for discrete very low

frequency emissions observed at Varanasi

A K SINGH¹, S B SINGH¹ and R P SINGH²

¹Department of Physics, Maharaja College, V.K.S. University, Arrah 802 301, India

²Physics Department, Banaras Hindu University, Varanasi 221 005, India

E-mail: abhay{\_}s@rediffmail.com

Abstract. A new type of discrete VLF emissions recorded at the low-latitude ground

station Varanasi (geomag. lat. 14$^{\circ}$55$'$ N, geomag. long.

154$^{\circ}$E; $L = 1.07$) during the strong magnetic activity on

29--30 April 1990 have been reported. A generation mechanism for various temporal and spectral features of discrete VLF emissions recorded at Varanasi is presented on the

basis of cyclotron resonance interaction between whistler mode wave and

energetic electrons ejected by substorm electric fields. An attempt is also

made to determine parallel energy and wave growth relevant to the generation

process of discrete VLF emissions. Finally, our results are discussed with

other published works.

Keywords. Physics of magnetosphere; trapped particles; waves:

propagation and excitation.

PACS Nos 94.30.-d; 94.30.-Hn; 94.30.-Tz