Lightning sferics and stroke‐delayed pulses measured in the stratosphere: Implications for mesospheric currents

Abstract

[1] During the Brazil Sprite Balloon Campaign 2002 -03, the vector ELF to VLF (25 Hz -8 kHz) electric and magnetic fields driven by cloud-to-ground (CG) lightning strokes at horizontal distances of 75 -600 km were measured at altitudes of 30-35 km. Electric field changes were measured for each of the 2467 CG strokes detected by the Brazilian Integrated Lightning Network. ELF pulses that occur 4 -12 ms after the retarded time of the lightning sferic, which have been previously attributed to sprites, were found for 1.4% of 934 strokes examined. Thus, lightning-driven electric and magnetic field changes were common and stroke-delayed ELF pulses were rare, which disagrees with results from the Sprites99 Balloon Campaign. Citation: Thomas, J. N., R. H. Holzworth, M. P.McCarthy, and O. Pinto Jr. (2005), Lightning sferics and strokedelayed pulses measured in the stratosphere: Implications for mesospheric currents, Geophys.

Simultaneous radio and satellite optical measurements of high‐altitude sprite current and lightning continuing current

“…In light of this tight time correlation, the absence of these pulses except at sprite times, and the theoretical analysis showing that such pulses are expected if sprites modify the local electric conductivity of the atmosphere [ Pasko et al , 1998], it is generally thought that such pulses are evidence of sprite current flowing in a small subset (around 10%) of sprites [ Cummer , 2003]. Balloon measurements of the occurrence of this class of pulse are consistent with ground measurements [ Thomas et al , 2005]. This evidence, however, is still circumstantial, and there is a well‐known lightning process, the M‐component [ Rakov and Uman , 2003, p. 176], that radiates in a similar manner.…”

Lightning‐driven electric fields measured in the lower ionosphere: Implications for transient luminous events

“…Only nearby in situ measurements can determine if the magnitudes and relaxation times of the nearby lightning‐driven quasi‐electrostatic fields (QSF) and electromagnetic pulses (EMPs) above thunderstorms are sufficient for TLE production and growth. Recent studies have reported lightning‐driven QSFs and EMPs in the stratosphere at about 35 km altitude [ Holzworth et al , 2005; Thomas et al , 2005a, 2005b]. We present, for the first time, in situ measurements in the upper mesosphere and lower ionosphere that have been analyzed to specifically address TLE production.…”