Formulation of Microsecond and Sub-microsecond Fluctuations in Geomagnetic Field due to Lightning

Abstract

Intracloud, positive and negative CG-lightning, exhibit microsecond and sub-microsecond scale waveforms in the in-situ electric field with average angular frequency (ω) ≈ O (103 to 105); sometimes even as high as ≈ O (107) due to   the ‘lightning-bursts’. The electric field fluctuations induce corresponding variability in ensuing induced magnetic field - though not identically. Hence spontaneous fluctuations are expected in total magnetic field, too. Fluctuations in induced magnetic field may be formulated as B = B0Cos( ωt) + BB. The horizontal component of the concentric circles of induced magnetic field interferes with in-situ linear  geomagnetic field(Gm) and causes corresponding micro and sub-microsecond fluctuations which could be formulated as B = B0Cos( ωt) + BBm (where BBm =  BB +  Gm ; a vectorial addition).  There will be a diameter-axis for the azimuthal induced magnetic field concentric circles, interfering with the in-situ geomagnetic field, where optimum fluctuations (maximum in one half and minimum in other half) will be experienced. The formulation has its application within corona envelope wherein the Lorentz force has to be accounted as an additional body force during the magnetohydrodynamic analysis of the atmospheric momentum equations.