共 51 条
Accelerated steady-state electrostatic particle-in-cell simulation of Langmuir probes
被引:4
作者:
Werner, Gregory R.
[1
]
Robertson, Scott
[1
]
Jenkins, Thomas G.
[2
]
Chap, Andrew M.
[2
]
Cary, John R.
[1
]
机构:
[1] Univ Colorado, Ctr Integrated Plasma Studies, Boulder, CO 80309 USA
[2] TechX Corp, 5621 Arapahoe Ave Suite A, Boulder, CO 80303 USA
基金:
美国国家科学基金会;
关键词:
POSITIVE-ION COLLECTION;
DUST PARTICLES;
CURRENT FLOW;
PLASMA;
MODEL;
CURRENTS;
OBJECT;
CHARGE;
D O I:
10.1063/5.0072994
中图分类号:
O35 [流体力学];
O53 [等离子体物理学];
学科分类号:
070204 ;
080103 ;
080704 ;
摘要:
First-principles particle-in-cell (PIC) simulation is a powerful tool for understanding plasma behavior, but this power often comes at great computational expense. Artificially reducing the ion/electron mass ratio is a time-honored practice to reduce simulation costs. Usually, this is a severe approximation. However, for steady-state collisionless, electrostatic (Vlasov-Poisson) systems, the solution with reduced mass ratio can be scaled to the solution for the real mass ratio, with no approximation. This "scaled mass " method, which works with already-existing PIC codes, can reduce the computation time for a large class of electrostatic PIC simulations by the square root of the mass ratio. The particle distributions of the resulting steady state must be trivially rescaled to yield the true distributions, but the self-consistent electrostatic field is independent of the mass ratio. This method is equivalent to "numerical timestepping, " an approach that evolves electron and ion populations with different time steps. Numerical timestepping can be viewed as a special case of the speed-limited PIC (SLPIC) method, which is not restricted to steady-state phenomena. Although the scaled-mass approach is simplest, numerical timestepping and SLPIC more easily generalize to include other effects, such as collisions. The equivalence of these new approaches is demonstrated by applying them to simulate a cylindrical Langmuir probe in electron-argon plasma, speeding up simulation by two orders of magnitude. Methods such as SLPIC can therefore play an invaluable role in interpreting probe measurements by including geometric effects, collisions, secondary emission, and non-Maxwellian distributions.
引用
收藏
页数:12
相关论文