Charged-particle chaotic dynamics in rotational discontinuities

Area of Science:

• Space Physics
• Plasma Physics
• Astrophysics

Background:

• Interplanetary plasma exhibits complex structures, including magnetic field discontinuities.
• These structures can originate in the solar corona or form from solar wind turbulence.
• Magnetic field variations significantly affect energetic particle propagation.

Purpose of the Study:

• To numerically model the interaction between charged particles and ideal magnetohydrodynamics rotational discontinuities.
• To investigate the influence of various parameters on particle motion across these structures.

Main Methods:

• Setting up a numerical model simulating charged particle interaction with rotational discontinuities.
• Analyzing particle trajectories based on parameters like rotation angle, magnetic field orientation, and initial particle conditions (pitch angle, gyrophase).

Main Results:

• Particle motion across discontinuities is complex and highly sensitive to initial conditions, showing transitions to chaotic behavior.
• Particles can become temporarily trapped within rotational discontinuities, with trapping times following a power-law distribution.
• The phase space separatrix between crossing and noncrossing trajectories exhibits a fractal structure.

Conclusions:

• The interaction of charged particles with rotational discontinuities is intricate and highly dependent on initial conditions.
• Fractal structures and particle trapping phenomena have significant implications for understanding energetic particle propagation in space plasmas.
• This study provides insights into the complex dynamics governing energetic particles in the heliosphere.