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From fluid/particle toward Complex Particle Kinetic models. Merging for
Complex Particle Kinetic modeling of multiple plasma beams (inter-penetrating
flows)
Lipatov, A.S.
GEST Center UMBC/NASA GSFC, Code 673, Greenbelt, MD 20771, USA
Abstract
We suggest a merging procedure for the Complex Particle Kinetic (CPK) model in case of interpenetrating flow (multiple plasma beams). Each CPK macro-particle includes a Maxwellian distribution in velocity and Gaussian distribution in space with internal dynamics (see [1], for details). It
is assumed that an arbitrary distribution of real particles can be represented by such a superposition
in phase space (moving-finite-element with time-dependent shape function) at least as well as could
be done with the standard particle in cell (PIC)/Monte Carlo (MC) delta functions and their associated “shape factors”. The CPK method allows us to provide a global simulation of the complex
plasma objects on the Hall-MHD (fluid) scale (aggressive merging) with automatic incorporation of
the kinetic/particle description of the particle-wave processes (aggressive fragmentation) where it is
necessary. The CPK approximation works well for ions, electrons, dust grains and neutral components. This code was tested in the simulations for the study of the interaction of the plasma flow
with comets and Io’s atmosphere.
In this report we examine the standard (PIC) and the CPK methods in the case of the simulation of
the particle acceleration by shock surfing. The plasma dynamics is described by a standard (particleion–fluid-electron) hybrid model (see, e.g. [3]). We also examine the fourth moment [2] and the
one-side moment [1] of the velocity distribution approaches for a particle fragmentation.
While a particle-mesh method is well enough verified approach, the CPK model seems to be a good
approach in case of multiscale simulation which includes multiple subdomains with various particle/fluid plasma behavior. However, the CPK model is still need in verification for a study the basic
plasma phenomena: particle heating and acceleration by collisionless shocks, magnetic field reconnection, beam dynamics, global multiscale simulation of the magnetospherical plasma near moons,
solar wind-planet interaction, heliospherical plasma, solar flares, CME, laser produced plasma etc.
In case of a study the complex multiscale plasma systems, the CPK method allows us to reduce the
computational resources by factor of 100-1000 as it needs with standard PIC methods. A.S.L. thanks
D.W. Hewett and D.J. Larson (Lawrence Livermore National Laboratory) for their helpful discussion
of the CPK technique.
References
[1] Hewett, D.W., Fragmentation, merging, and internal dynamics for PIC simulation with finite size
particles, J. Comput. Phys. 189, 390, 2003.
[2] Larson, D.J., A coulomb collision model for PIC plasma simulation, J. Comput. Phys. 188, 123,
2003.
[3] Lipatov, A.S., The Hybrid Multiscale Simulation Technology. An Introduction with Application
to Astrophysical and Laboratory Plasmas, Springer, Berlin, Heidelberg, New York, 2002, pp. 403.
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