Using VLF Transmitter Signals at LEO for Plasmasphere Model Validation

Abstract

This study presents analysis of very low frequency (VLF) transmitter signal measurements on the Very‐Low‐Frequency Propagation Mapper (VPM) CubeSat in low‐Earth orbit. Six months of satellite operation provided good data coverage, used to build global statistical maps of VLF power distribution. The power distribution above four powerful transmitters is used as input for ray tracing to study signal propagation to the conjugate hemisphere in two plasmaspheric density models. The ray tracing results are further compared with VPM measurements to determine which model provides better agreement with observations. As ray propagation largely depends on the background plasma density distribution, this indirect method can be used for plasmaspheric density model validation as an alternative to multipoint in situ plasma measurements that may not be readily obtainable. In addition, it can be used to investigate Landau damping and ducted versus non‐ducted propagation of VLF signals.

Resolution of a Few Problems in the Application of Quasilinear Theory to Calculating Diffusion Coefficients in Heliophysics

“…Glauert and Horne (2005) parameterize g ( X ) as a Gaussian with peak value X m and width X w , $$g(X)={e}^{-{\left(\left(X-{X}_{m}\right)/{X}_{w}\right)}^{2}}$$; thus, if X w is very small, Equation will produce nearly identical results to those in Equation , that is, the equation used in Glauert and Horne (2005). This situation might apply to calculating diffusion coefficients for ground‐based very low‐frequency (VLF) transmitters, for example, the waves from which exit the ionosphere propagating at nearly a single wave normal angle at each location above the transmitter (Usanova et al., 2022). Equations and may also give nearly the same result if X max ≪ X r ( ω ), where $${X}_{r}^{2}(\omega )=-P/S$$ is the squared tangent of the resonance cone angle, because the Jacobian may be nearly constant over the domain of integration and can hence be pulled out of the integral.…”

Spatial and Temporal Distribution of Northwest Cape Transmitter (19.8 kHz) Radio Signals Using Data Collected by the China Seismo-Electromagnetic Satellite

“…Zhang et al [28] suggested that ducted signals account for only a minority of the propagation of ground-based VLF transmitters in the magnetosphere, while non-ducted modes dominate. Recently, the study by Usanova et al [29] also found that the signals from VLF transmitters between L-shells of 1.17 and 2.87 are dominated by non-ducted propagation. Therefore, the propagation characteristics of VLF waves in the ionosphere are still worth studying.…”

Modeling the Propagation of Extremely Low Frequency Electromagnetic Emissions From the Power Lines to the Inner Magnetosphere in a Dipole Field

“…Man‐made electromagnetic (EM) emissions in the extremely low frequency (ELF) and very low frequency (VLF) range are extensively observed in the ionosphere and magnetosphere (e.g., Bullough et al., 1976; Parrot, 2018), which can impact the dynamics of energetic electrons in the radiation belts (e.g., Hua et al., 2020; Inan et al., 2003). Apart from VLF transmitters (e.g., Cohen & Inan, 2012; Usanova et al., 2022; Xia et al., 2023), ELF transmitters (e.g., Fedorov et al., 2023; Pilipenko et al., 2019) and modulated heating of the ionosphere (e.g., Eliasson et al., 2012; Piddyachiy et al., 2008), electric power transmission lines in the industrial areas are also very important sources contributing to the man‐made VLF and ELF emissions (e.g., Bullough, 1995; Fedorov et al., 2021; Lizunov et al., 2023; Němec et al., 2022; Park & Helliwell, 1978; Wu et al., 2023).…”