Can Multi-threaded Flux Tubes in Coronal Arcades Support a Magnetohydrodynamic Avalanche?

Area of Science:

• Plasma Physics
• Solar Physics
• Astrophysics

Background:

• Magnetohydrodynamic (MHD) instabilities are crucial for energy release from stressed magnetic fields in astrophysical plasmas.
• Previous models focused on cylindrical flux tubes, but recent studies consider curved arcades with both footpoints in the same plane.
• Multi-threaded cylindrical flux tubes can exhibit MHD avalanches, where one unstable thread destabilizes others.

Purpose of the Study:

• To investigate the properties of multi-threaded coronal loops in realistic, curved arcade structures.
• To analyze the evolution and instability of both single- and multi-threaded coronal loops under varying photospheric driving conditions.
• To understand how geometry and relative driving speeds influence instability propagation in multi-threaded systems.

Main Methods:

• Utilizing three-dimensional MHD simulations to model the dynamic evolution of coronal loops.
• Simulating both single-threaded and multi-threaded loop configurations.
• Varying the driving velocity of individual threads to observe effects on stability and energy release.

Main Results:

• Single-threaded loops destabilize consistent with ideal MHD instability, as seen in prior research.
• The presence of multiple threads alters instability dynamics, with geometry and driving speeds playing key roles in thread-to-thread destabilization.
• Continuous driving of disrupted thread remnants leads to secondary, aperiodic energetic bursts in both single- and multi-threaded scenarios.

Conclusions:

• Curved coronal arcades with multi-threaded loops exhibit complex MHD instability behavior.
• The interplay between loop geometry, driving speeds, and the number of threads significantly impacts energy release dynamics.
• Secondary energy bursts can be triggered by continuous driving, highlighting the potential for complex energy release processes in the solar corona.