Single Particle Dynamics in a Compact Fusion Reactor

doi:10.19596/j.cnki.1001-246x.8415

Abstract

Abstract:

For the unique magnetic structure of a compact fusion reactor, confinement dynamics of a single high-energy charged particle was studied with Monte Carlo method. Taking into account the local flatness characteristics of the magnetic field configuration, a charged particle moves basically in a constant magnetic field for a sufficiently small area or a short enough timestep. Therefore, a point-by-point analytical solution of particle motion equation that guarantees accurately conservation of energy is proposed, which has long-term tracking capabilities. Simulation results show that for high-energy deuterium particles with 1 keV energy distributed randomly in initial position and velocity direction, there is about a 7% probability that can be constrained to an order of 10 ms. Since the method for solving the motion equation is independent of magnetic configuration, it can be generalized naturally to arbitrary magnetic confinement setup.

Key words: compact fusion reactor, single charged particle motion, magnetic trap

Chengxin YU, Xiaofang SHU, Jie LIU. Single Particle Dynamics in a Compact Fusion Reactor[J]. Chinese Journal of Computational Physics, 2022, 39(3): 253-260.

Figures/Tables 8

Fig.1 Conception design of a compact fusion reactor (CFR)

Table 1 The adopted parameters for CFR

C_ℓ	y_ℓ/m	r_ℓ/m	I_ℓ/MA
C₁	-1.25	0.3	-10
C₂	-1.0	0.5	-1
C₃	-0.7	0.7	-1
C₄	-0.4	0.25	7
C₅	0	0.702	-4.3
C₆	0.4	0.25	7
C₇	0.7	0.7	-1
C₈	1.0	0.5	-1
C₉	1.25	0.3	-10

Fig.2 (a) Magnetic configuration (logarithmic scale); (b) Zoom-in version of the center of (a) (The blue stream lines show direction and strength of the magnetic field.)

Fig.3 (a) Axial properties of the magnetic field; (b) Two-dimensional decomposition of three-dimensional magnetic field; (c) Decomposition of lateral magnetic component

Fig.4 Three-dimensional grids used in simulation programs

Fig.5 Evolution of relative error of kinetic energy

Fig.6 Distributions of 105 random deuterium samples at different moments in the magnetic trap of CFR (a) 10-7 s；(b) 10-6 s；(c) 10-5 s；(d) 10-4 s；(e) 10-3 s；(f) 10-2 s

Fig.7 Convergence of algorithm at three different step lengths for 100000, 25000 and 5000 samples, respectively

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