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22-27 October 2018
Mahatma Mandir Conference Centre
Asia/Kolkata timezone
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Numerical Relaxation of a 3D MHD Taylor-Woltjer State Subject to Abrupt Expansion

25 Oct 2018, 08:30
4h
Mahatma Mandir Conference Centre

Mahatma Mandir Conference Centre

Gandhinagar (nearest Airport: Ahmedabad), India
Poster P5 Posters

Speaker

Mr Rupak Mukherjee (Institute for Plasma Research)

Description

Rupak Mukherjee, Rajaraman Ganesh Institute for Plasma Research, HBNI, Gandhinagar, Gujarat, India, 382428. ganesh@ipr.res.in Since the advent of Taylor-Woltjer theory [1,2], it has been widely believed that situations with perfectly conducting boundaries and near ideal conditions, the final state of MHD system would be force-free Taylor-Woltjer states defined as curl B = alpha B with alpha as a constant and B is the magnetic field defined over a volume V. These states are of fundamental importance in fusion plasmas [3]. More recently, several new MHD models have been proposed – for example Reduced Multi-region relaxed MHD [4] and arbitrary scale relaxation model to Taylor-Woltjer state [5] to mention a few. In the present work, we use a 3D compressible MHD solver in cartesian geometry which can handle conducting or periodic as well has mixed boundary conditions to investigate numerically the arbitrary scale relaxation model proposed by Qin et al [5]. For this purpose, we consider two volumes V_init and V_final. We load the 3D MHD solver in the limit of zero compressibility with a Taylor-Woltjer state B_init(x,y,z,t=0) and let it again a numerical evolve with conducting boundaries at V_init to make sure that we have obtained a numerically steady Taylor-Woltjer state for volume V_init. Followed by this procedure, we ``suddenly'' relax the boundaries to a new volume V_final, such that V_init < V_final and evaluate whether or not the system attains quasi-steady state. Details of the numerical method used, the protocol followed, the expansion technique and the novelty of this numerical experiment and details of our results will be presented. References [1] J. B. Taylor, Phys. Rev. Lett, 33, 1139 (1974) [2] L. Woltjer, Proc. Nat. Acad. Sci U.S.A , 44, 489 (1958) [3] J. B. Taylor, Rev. Mod. Phys. 58, 741 (1986) [4] S R Hudson et al, Phys. Plasmas, 19, 112502 (2012) [5] H. Qin et al, Phys. Rev. Lett. 109, 235001 (2012)
Paper Number TH/P5-3
Country or International Organization India

Primary author

Mr Rupak Mukherjee (Institute for Plasma Research)

Co-author

Dr Rajaraman Ganesh (Institute for Plasma Researh, Bhat Village, Gandhinagar 382428, Gujarat, INDIA)

Presentation Materials

Paper