Earth-Based Transmitters Trigger Precipitation of Inner Radiation Belt Electrons: Unveiling Observations and Modeling...

Area of Science:

• Space Physics
• Plasma Physics
• Atmospheric Science

Background:

• Human activities, such as electromagnetic signal transmission, influence the near-Earth space environment.
• Energetic electrons in Earth's inner radiation belt are typically observed with a single wisp-like energy distribution.
• This phenomenon is usually attributed to first-order cyclotron resonance with transmitter signals.

Purpose of the Study:

• To report the first observation of multiple wisps of precipitating energetic electrons in Earth's inner radiation belt.
• To investigate the underlying wave-particle interaction mechanisms responsible for these multiple wisps.
• To explore the implications for space weather and radiation belt remediation.

Main Methods:

• Utilized data from the Relativistic Electron and Proton Telescope integrated little experiment-2 (REPTile-2) on the Colorado Inner Radiation Belt Experiment (CIRBE) CubeSat.
• Conducted simulations to analyze the wave-particle interactions.
• Examined the role of harmonic cyclotron resonances and oblique transmitter signals.

Main Results:

• Observed multiple distinct wisps of precipitating energetic electrons for the first time.
• Demonstrated that harmonic cyclotron resonances (1st, -1st, and 2nd order) of highly oblique NWC transmitter signals produce these multiple wisps.
• Confirmed the occurrence of multiple-order cyclotron resonances simultaneously in space.

Conclusions:

• The simultaneous occurrence of multiple-order cyclotron resonances advances our understanding of wave-particle interactions in near-Earth space.
• This discovery has significant implications for developing artificial radiation belt remediation strategies.
• It also enhances our knowledge of plasma wave propagation and scattering within planetary magnetospheres.