[P-EM13] Dynamics of the Inner Magnetospheric System

[PEM13-12] Understanding unsual ‘high-frequency’ bursty-patches using VLF-CHAMP

*Claudia Martinez-Calderon¹, Jyrki Manninen², Kazuo Shiokawa¹, David Pisa³ (1.ISEE, Nagoya University, 2.Sodankyla Geophysical Observatory, University of Oulu, 3.Institute of Atmospheric Physics, Czech Academy of Sciences, Prague, Czechia )

Keywords:VLF/ELF, bursty-patches, wave propagation, VLF waves

Extremely Low (ELF) and Very Low Frequency (VLF) emissions are naturally occurring magnetospheric plasma waves detected between frequencies of 3 Hz to 30 kHz. They play a fundamental role in radiation belt dynamics, accelerating or scattering electrons through wave-particle interactions. Bursty-patches are a recently discovered type of VLF emission detected at frequencies above half the electron gyrofrequency in the equatorial plane for the L-shell of observation. Their characteristics and particular propagation to the ground are still unknown.

Here we will use data from the three VLF receiver stations in Finland to discuss the properties and propagation of bursty-patches to the ground. We will use data from Kannushleto (KAN, MLAT=65.0°N, L=5.5) active since 2006, Oulujarvi (OUJ, MLAT=61.3°N, L=4.4) since 2022, and Angeli (ANG, MLAT=66.1°N, L=6.3) since August 2024. We will use statistics and combine simultaneous and conjugated one-to-one correspondence events to assess the uniqueness of bursty-patches and their relationship to more usual VLF waves, such as chorus or hiss. We will address particularly the question of the specific wave path that bursty-patches follow from the magnetosphere to the ground.