Aleksandr M. Rubenchik

Computer simulation of Langmuir collapse

Abstract The problem of Langmuir wave collapse in 2D and 3D plasma is considered. A new approach for computer simulation of this phenomenon is proposed, which includes two different theoretical models: averaged dynamical equations and Vlasovs set of equations. It allows to take into account all essential effects during the whole process of collapse and, hence, to get a reliable picture of the collapse in detail and to save markedly computer resources. Peculiarities of the numeric methods are also discussed.

Interaction of counter-streaming plasmas

The possibility of hot dense plasma creation for the filling of open traps by thermalization of the direct energy of supersonic plasma clusters accelerated by electrodynamic accelerators has been studied theoretically and experimentally. The mean free path of particles in these traps, as a rule, exceeds typical system size, therefore, it is of great interest to study the turbulent mechanisms of counter-streaming plasmas relaxation. A calculation of relaxation length is very important because such turbulent relaxation of counter-streaming plasmas is observed experimentally. Investigation of counter-streaming plasma interaction is of general physical concern. Such situations occur, for example, in astrophysics: the shock wave structure problem, the relaxation of ionosphere plasma flow behind satellites, the spreading of laser-produced plasma in surrounding gas, etc. A detailed discussion is given of the relaxation of counter-streaming plasma due to turbulent mechanisms: the two-stream ion-acoustic instability.

A particle model for three-dimensional Langmuir collapse simulation

Abstract The numerical simulation of the final stage of Langmuir collapse requires three-dimensional kinetic consideration and thus is at the limit of todays computer capability. We have managed to solve this problem by making systematic use of the theoretically known fundamental physical properties of a collapsing cavity, and by taking every possible measure to match the physical parallelism of the problem with the architecture of the multiprocessor complex used. The pecularities of the numerical model, the software and hardware implementation principles of this model, and also a number of the results of the simulation are presented.

A noncollisional mechanism for plasma species separation

Abstract A noncollisional mechanism for the separation of ion species moving through a plasma is proposed. The results of a numerical simulation prove the possibility of anomalous quick spatial separation of ion species on the scale of about 200 Debye radii.

On powerful electron beam relaxation in magnetized plasmas

Abstract A simulation of electron beam interaction with a magnetized plasma is presented. Fast relaxation to a plateau state takes place. The parameters of the plateau are estimated.