3 papers
physics.ao-ph2026
Similarities in the Initiation of Upward Positive and Downward Negative Lightning Flashes
Toma Oregel-Chaumont, Mohammad Azadifar, Antonio Å unjerga +2
This study examines the relationship between upward negative stepped leader pulses in upward positive lightning and preliminary breakdown pulses (PBPs) in downward negative lightni…
physics.plasm-ph2025
Underlying Physical Mechanisms in Upward Positive Flashes
Toma Oregel-Chaumont, Antonio Šunjerga, Jérôme Kasparian +2
This study presents the first observation of a mixed mode of charge transfer during an upward positive flash, which was initiated from the Säntis Tower in Switzerland. High-speed…
physics.optics2025
Cartesian and spherical multipole expansions in anisotropic media
Elias Le Boudec, Toma Oregel-Chaumont, Farhad Rachidi +2
The multipole expansion can be formulated in spherical and Cartesian coordinates. By constructing an explicit map linking both formulations in isotropic media, we discover a lack o…