Photonic superdiffusive motion in resonance line radiation trapping Partial frequency redistribution effects

Area of Science:

• Atomic physics
• Radiative transfer
• Spectroscopy

Background:

• Radiation trapping is crucial in astrophysical and laboratory plasmas.
• Understanding spectral line profiles requires accounting for frequency redistribution.
• Partial frequency redistribution (PFR) complicates standard models.

Purpose of the Study:

• To generalize the opacity distribution function for PFR.
• To analyze the impact of PFR on jump length probability distributions.
• To investigate spectral line profiles under various broadening mechanisms.

Main Methods:

• Generalization of the single line opacity distribution function.
• Analysis of PFR effects on jump length probability distributions.
• Examination of spectral line profiles for different broadening scenarios (Doppler, natural, collisional).

Main Results:

• Identified two coexisting scales: PFR-dominated small scale and asymptotic large scale.
• Pure Doppler and combined natural, Doppler, and collisional broadening exhibit superdiffusive Levy flights.
• Combined natural and Doppler broadening shows anomalous small-scale and diffusive large-scale behavior.

Conclusions:

• The study highlights the critical role of PFR in radiation trapping dynamics.
• Assumptions of complete redistribution or frequency coherence are often incompatible with realistic broadening conditions.
• Findings impact the interpretation of spectral lines in various physical systems.