Lightning superbolts are the most powerful and rare lightning events with intense optical emission, first identified from space. Superbolt events occurred in 2010-2018 could be localized by extracting the high energy tail of the lightning stroke signals measured by the very low frequency ground stations of the World-Wide Lightning Location Network. Here, we report electromagnetic observations of superbolts from space using Van Allen Probes satellite measurements, and ground measurements, and with two events measured both from ground and space. From burst-triggered measurements, we compute electric and magnetic power spectral density for very low frequency waves driven by superbolts, both on Earth and transmitted into space, demonstrating that superbolts transmit 10-1000 times more powerful very low frequency waves into space than typical strokes and revealing that their extreme nature is observed in space. We find several properties of superbolts that notably differ from most lightning flashes; a more symmetric first ground-wave peak due to a longer rise time, larger peak current, weaker decay of electromagnetic power density in space with distance, and a power mostly confined in the very low frequency range. Their signal is absent in space during day times and is received with a long-time delay on the Van Allen Probes. These results have implications for our understanding of lightning and superbolts, for ionosphere-magnetosphere wave transmission, wave propagation in space, and remote sensing of extreme events.
Bibliographical noteFunding Information:
The authors thank the World Wide Lightning Location Network, a collaboration among over 50 universities and institutions, for providing the lightning location and energy data used in this paper. The work of J.-F.R., T.F., G.S.C., and E.H.L. was performed under the auspices of an agreement between CEA/DAM (Commissariat à l’Energie Atomique, Direction des Applications Militaires) and NNSA/DP (National Nuclear Security Administration, Defense Program) on cooperation on fundamental science. The authors acknowledge the International Space Sciences Institute (ISSI). The work of GSC was supported in part by the Defense Threat Reduction Agency (DTRA). Thanks also to DTRA for supporting a collaborative visit by JFR at Los Alamos National Laboratory in 2018. The work of DM was supported by the National Science Foundation under award 1841011. The authors thank the entire Van Allen Probes team, and especially the EFW and EMFISIS teams for their support.
© 2021, The Author(s).