EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Active Control of the Radiation Belt Particle Populations with Ionospheric Amplification of VLF Waves

Paul Bernhardt1, Man Hua2, Jacob Bortnik2, Quanli Ma2, Pekka Verronen3, Michael McCarthy4, Mark Golkowski5, Morris Cohen6, Andrew Howarth7, Gordon James7, and Nigel Meredith8
Paul Bernhardt et al.
  • 1University of Alaska Fairbanks, Geophysical Institute, United States of America (
  • 2Department Atmospheric and Oceanography Science, UCLA, Los Angeles, CA, USA (
  • 3Sodankylä Geophysical Observatory, Univ. Oulu, Sodankylä, Finland (
  • 4Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA (
  • 5Department of Electrical Engineering, Univ. of Colorado Denver, CO, USA (MARK.GOLKOWSKI@UCDENVER.EDU)
  • 6School of Electrical and Computer Engineering, Georgia Inst. of Technology, Atlanta, Georgia, USA (
  • 7Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada (
  • 8British Antarctic Survey, Natural Environment Research Council, Cambridge, UK (

Ground-based VLF transmitters located around the world generate signals that leak through the bottom side of the ionosphere in the form of whistler mode waves.  Wave and particle measurements on satellites have observed that these man-made VLF waves can be strong enough to scatter trapped energetic electrons into low pitch angle orbits, causing loss by absorption in the lower atmosphere.  This precipitation loss process is greatly enhanced by intentional amplification of the whistler waves in the ionosphere using a newly discovered process called Rocket Exhaust Driven Amplification (REDA).  Satellite measurements of REDA have shown between 30 and 50 dB intensification of VLF waves in space using a 60-second burn of the 150 g/s thruster on the Cygnus satellite that services the International Space Station (ISS) [Bernhardt et al. 2021; Bernhardt 2021].  This controlled amplification process is adequate to deplete the energetic particle population in the radiation belts in a few minutes rather than the multi-day period it would take naturally.  Numerical simulations of the pitch angle diffusion for radiation belt particles use the UCLA quasi-linear Fokker Planck model (QLFP) to assess the impact of REDA on radiation belt remediation (RBR) of newly injected energetic electrons [Bernhardt et al., 2022].  The simulated precipitation fluxes of energetic electrons are applied to models of D-region electron density and bremsstrahlung x-rays for predictions of the modified environment that can be observed with satellite and ground-based sensors.   


Bernhardt, P.A., et al., Strong Amplification of ELF/VLF Signals in Space Using Neutral Gas Injections from a Satellite Rocket Engine (2021), Radio Science, 56(2), e2020RS007207, 2020RS007207.

Bernhardt, P.A., The Whistler Traveling Wave Parametric Amplifier (WTWPA) Driven by an Ion Ring-Beam Distribution from a Neutral Gas Injection in Space Plasmas (2021), IEEE Transactions on Plasma Science. 49, 6, 1983-1996, DOI: 10.1109/TPS.2021.3079130.

Bernhardt, P.A., et al., Active Precipitation of Radiation Belt Electrons using Rocket Exhaust Driven Amplification (REDA) of Man-Made Whistlers, Submitted to the Journal of Geophysical Research, 2022.

How to cite: Bernhardt, P., Hua, M., Bortnik, J., Ma, Q., Verronen, P., McCarthy, M., Golkowski, M., Cohen, M., Howarth, A., James, G., and Meredith, N.: Active Control of the Radiation Belt Particle Populations with Ionospheric Amplification of VLF Waves, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2836,, 2022.


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