LASP Magnetosphere Seminars

Abstract

Lightning-generated whistlers (LGWs) are electromagnetic waves generated by lightning strikes that can enter Earth’s magnetosphere and interact with radiation belt electrons, causing them to precipitate into the atmosphere. A hallmark of this lightning-induced electron precipitation (LEP) is a unique type of microbursts, which have regularly spaced pulses known as bouncing packets, linked to the bounce motion of resonant electrons. This study examines precipitation driven by ducted LGWs using test-particle simulations and quasilinear diffusion theory for electrons between 10 keV and 10 MeV. Results show that a single LGW can trigger precipitation bursts lasting several to ten seconds, with rapid sub-second variations. The precipitation consists of both structured microbursts and a smoother background component, the latter often mistaken for trapped electrons. Comparison with SAMPEX satellite observations indicates that LEP timing and structure depend on the ambient electron spectrum, plasma duct characteristics, and LGW frequency content. The findings suggest that previous studies may have underestimated LGW-driven precipitation and its impact on radiation belt electron loss. Overall, the results reveal the dual role of LGWs in producing both bursty and continuous precipitation, improving understanding of magnetosphere–ionosphere coupling.