Writhed Analytical Magnetic Flux Rope Model.

Area of Science:

• Space Physics
• Plasma Physics
• Astrophysics

Background:

• Magnetic clouds within interplanetary coronal mass ejections (ICMEs) are often modeled as flux ropes.
• Existing flux rope models typically assume cylindrical or toroidal geometries and axial invariance.
• Solar wind and other influences can deform ICME flux ropes along their axes.

Purpose of the Study:

• To develop a novel analytical model for writhed magnetic flux ropes.
• To describe flux rope structures with varying curvature and torsion, moving beyond constrained geometries.
• To analytically model flux ropes with circular cross-sections of constant size.

Main Methods:

• Parametrization of the flux rope axis and use of a parallel transport frame.
• Derivation of axial and poloidal magnetic field components assuming conserved axial magnetic flux.
• Development of a general class of solutions based on integration constants.

Main Results:

• The study presents a new class of analytical solutions for magnetic flux ropes.
• It is found that magnetic field twist locally changes when the geometry deviates from cylindrical or toroidal forms.
• The model generates novel in situ magnetic field profiles distinct from traditional models.

Conclusions:

• The developed writhed flux rope model provides a more flexible description of ICME magnetic structures.
• This approach allows for the investigation of non-axisymmetric and deformed flux rope geometries.
• The findings offer new possibilities for interpreting in situ observations of ICMEs.