MHD simulation on magnetic compression of field reversed configurations with NIMROD

Journal Article · Mon Mar 06 00:00:00 EST 2023 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/acbdac· OSTI ID:1961464

Ma, Y.; Zhu, P. ; Rao, B.; Li, H.

Abstract Magnetic compression has long been proposed a promising method for plasma heating in a field reversed configuration (FRC). However, it remains a challenge to fully understand the physical mechanisms underlying the compression process, due to its highly dynamic nature beyond the one-dimensional (1D) adiabatic theory model (Spencer et al 1983 Phys. Fluids 26 1564). In this work, magnetohydrodynamics simulations on the magnetic compression of FRCs using the NIMROD code (Sovinec et al 2004 J. Comput. Phys. 195 355) and their comparisons with the 1D theory have been performed. The effects of the assumptions of the theory on the compression process have been explored, and the detailed profiles of the FRC during compression have been investigated. The pressure evolution agrees with the theoretical prediction under various initial conditions. The axial contraction of the FRC can be affected by the initial density profile and the ramping rate of the compression magnetic field, but the theoretical predictions on the FRC’s length in general and the relation $r_s=\sqrt{2}{r}_o$ in particular hold approximately well during the whole compression process, where r _s is the major radius of FRC separatrix and r _o is that of the magnetic axis. The evolutions of the density and temperature can be affected significantly by the initial equilibrium profile and the ramping rate of the compression magnetic field. During the compression, the major radius of the FRC is another parameter that is susceptible to the ramping rate of the compression field. Basically, for the same magnetic compression ratio, the peak density is higher and the FRC’s radius r _s is smaller than the theoretical predictions.

• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: FG02-86ER53218
• OSTI ID: 1961464
• Alternate ID(s): OSTI ID: 1958068
• Journal Information: Nuclear Fusion, Journal Name: Nuclear Fusion Vol. 63 Journal Issue: 4; ISSN 0029-5515
• Publisher: IOP Publishing
• Country of Publication: IAEA
• Language: English