Abstract

Abstract The linear magnetohydrodynamic stability of a shielding magnetic flux rope with a surface current under coronal solar conditions is analyzed in the framework of an energy principle. The equation describing the potential energy change induced by disturbances of the equilibrium was derived. It has been shown that the surface reverse current shielding the azimuthal component of the magnetic field lines outside a flux rope stabilizes the development of kink- and flute-type instabilities in the long-wavelength limit independently of the cross-sectional radial profile of current density. Kink modes are the most unstable ones as their generation requires less energy than other modes. Based on the obtained dispersion relation for kink oscillations, we proposed a new expression for the determination of magnetic field components of the twisted loop.

Highlights

  • The magnetic flux tube and current sheets are the main “building blocks” of solar magnetic configurations

  • Kink instability is a subject of special interest since there is much evidence that this instability can be responsible for flare energy release and coronal mass ejections

  • The Kruskal–Schafranov condition has been obtained for a flux rope with an electric current surrounded by vacuum, with an accuracy of the coefficient the critical twist angle (Φc = 2.9π) is still valid for solar coronal loops anchored at footpoints

Read more

Summary

Introduction

The magnetic flux tube and current sheets are the main “building blocks” of solar magnetic configurations (see, e.g., Parker 1979; Priest 1984; Priest & Forbes 2000; Ryutova 2018). The main aim of this work is to investigate the stability of the partially isolated magnetic flux rope with a shielding surface current under solar coronal conditions on the basis of an energy principle (Bernstein et al 1958). This method has been used previously for theoretical investigation of the solar coronal loops (e.g., Priest 1984; Hood 1986; Melville et al 1986; Linton et al 1996) but shielding longitudinal currents had not been considered.

An Energy Principle for a Flux Rope with Sharp Boundary
The Eigenfunctions
The Stability of the Kink Mode
Discussion and Conclusions

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.