Could 3I/ATLAS emit radio emission at 440±10 Hz from magnetohydrodynamic instabilities in rotation-modulated current sheets?

Preprint Dynamical and Electromagnetic Analysis of 3I/ATLAS

Electromagnetic Emission from Cometary Plasmas

At 3.3 AU, CO2 outgassing at 1.7×10^27 molecules/s generates a dense plasma coma. Solar UV photons ionize approximately 0.1% of this gas, producing approximately 1.7×10^24 electrons/s. With an expansion velocity of approximately 0.5 km/s, ions and electrons fill a region approximately 1,000 km in radius before recombination occurs.

This yields an electron density of ne ≈ 2.4×10^3 cm^−3. The corresponding plasma

frequency is: fp ≈ 440 Hz (1)

This represents the natural oscillation frequency of the coma plasma. As jets modulate plasma density on the comet’s 16.16 hr rotation period, radio emission should vary

accordingly. The jet-driven density variations maintain constant plasma frequency, but

emission intensity oscillates with the rotation period, creating a distinctive observational

signature.

Radio emissions have been detected from several solar system comets through plasma

oscillation mechanisms (Brosius et al., 1989; Hoang et al., 1998). The unique chemical

composition and rotational properties of 3I/ATLAS may generate distinctive electromagnetic signatures observable through ground-based radio telescopes, particularly during enhanced activity periods near perihelion.