Thunderstorms, lightning, sprites and magnetospheric whistler-mode radio waves

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Thunderstorms and the lightning that they produce are inherently interesting phenomena that have intrigued scientists and mankind in general for many years. The study of thunderstorms has rapidly advanced during the past century and many efforts have been made towards understanding lightning, thunderstorms and their consequences. Recent observations of optical phenomena above an active lightning discharge along with the availability of modern technology both for data collection and data analysis have renewed interest in the field of thunderstorms and their consequences in the biosphere. In this paper, we review the electrification processes of a thunderstorm, lightning processes and their association with global electric circuit and climate. The upward lightning discharge can cause sprites, elves, jets, etc. which are together called transient luminous events. Their morphological features and effects in the mesosphere are reviewed. The wide spectrum of electromagnetic waves generated during lightning discharges couple the lower atmosphere with the ionosphere/magnetosphere. Hence various features of these waves from ULF to VHF are reviewed with reference to recent results and their consequences are also briefly discussed.

💡 Research Summary

The paper provides a comprehensive review of the electrical and electromagnetic phenomena associated with thunderstorms, lightning, and their upper‑atmospheric and magnetospheric consequences. It begins by outlining the fundamental electrification processes within a thunderstorm: collisions between ice particles, graupel, and supercooled water droplets generate charge separation, while strong updrafts concentrate positive charge near the cloud top and negative charge near the base. This results in potential differences of several hundred megavolts, setting the stage for lightning initiation.

Lightning discharge is then dissected into three stages—leader formation (initial ionization), return stroke (conductive channel), and subsequent continuing currents. Each stage emits a distinct electromagnetic spectrum ranging from ultra‑low‑frequency (ULF) and extremely low‑frequency (ELF) waves that couple to the global electric circuit, to very‑low‑frequency (VLF) and very‑high‑frequency (VHF) emissions that propagate through the ionosphere into the magnetosphere. The authors emphasize that VLF waves can trigger plasma instabilities, accelerate electrons and ions, and are observable as phase‑shifts and spectral broadening in satellite data.

A major focus of the review is the family of transient luminous events (TLEs) generated by upward lightning discharges. Sprites, occurring at 50–90 km altitude, are large‑scale electrical breakdowns caused by rapid voltage spikes that locally collapse the lower ionosphere. Elves are brief (tens of microseconds) optical flashes produced when electromagnetic pulses from lightning strike the base of the ionosphere, generating expanding rings of emission. Blue jets, observed between 30 and 50 km, are narrow upward propagating luminous channels linked to strong positive charge transport. The paper discusses how these phenomena modify mesospheric chemistry, notably increasing NOx and ozone precursor concentrations, and argues that such changes should be incorporated into climate models.

The final technical section examines whistler‑mode radio waves generated by lightning. These waves travel along geomagnetic field lines, entering the magnetosphere where they interact resonantly with energetic electrons and protons. The resulting energy transfer can intensify radiation belt populations and alter ionospheric conductivity. Whistler observations from satellite and ground‑based VLF receivers provide diagnostics of plasma density and temperature, making them valuable tools for space‑weather monitoring.

Overall, the authors synthesize recent observational advances—high‑speed optical imaging, satellite radio‑frequency measurements, and sophisticated spectral analysis—to illustrate how thunderstorms act as a bridge linking the lower atmosphere, ionosphere, and magnetosphere. The multi‑scale electromagnetic coupling influences global electric currents, upper‑atmospheric chemistry, and magnetospheric dynamics, underscoring the need for integrated modeling efforts that span meteorology, atmospheric physics, and space science.