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In this page are collected all the numerical codes developed by the Author in the research field of plasma dynamics in Plasma Focus (PF) devices at the Nuclear Engineering Laboratory (LIN) of Montecuccolino.
The codes described below all behave to the microscopical investigation of the electrical breakdown of PFs, due to the discharge of an externally connected conderser bank onto the electrodes of the device. In order to retrieve complete informations about the forming plasma sheath at the end of the breakdown phase, macroscopical hydrodynamics codes could not be chosen since the strong deviation of the phase space distribution function of the species forming the plasma from the classical equilibrium (Maxwellian) one assumed as default in such codes. In particular, it was chosen to use Particle In Cell (PIC) techniques, coupled with a Monte Carlo Collisional (MCC) module for the modeling of the transition of the initially neutral filling gas into the plasma state, because of the simplicity but at the same time the strength of such techniques.
All the codes, fully developed by the Author, are distributed under the GNU Public License v. 3. The user may modify at will the Fortran90 sources as long as the ownership of the project is acknowledged to the Author.
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es-cPIF
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Version 1.08
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es-cPIF is an electrostatic-collisional Particle In Cell (PIC) code for Plasma Focus (PF) breakdown simulation. Both the external and the selfconsistent electrical fields are solved in a 2D domain representing the PF cross section, by means of a first order shape function and a classical SOR solver. The simulation particles are then pushed by a second order (leap-frog) integration scheme and checked for collision with neutral molecules by Monte Carlo method. An innovative technique (Hierarchycal Agglomerative Sub-Clustering, HASC) for the dynamic reduction of the simulation particles number is used due to the multiplication of this latter for avalanche ionization processes. Secondary Electrons Emission (SEE) phenomena from the boundaries are included to provide a sustainment source of new electrons for the Townsend mechanism.
The results produced by the code let the Author investigate the initial phases of the breakdown, together with a physical analysis of the mechanisms responsible of a plasma sheath seed formation.
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SAMRes-cPIF
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Version 0.3
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SAMRes-cPIF is an electro static- collisional Particle In Cell (PIC) code with Structured Adaptive Mesh Refinement (SAMR) for Plasma Focus (PF) breakdown simulation. It is an evolution of the es-cPIF code, developed within the open source framework SAMRAI, created and maintained by the Center for Applied Scientific Computing (CASC) at Lawrence Livermore National Laboratory (LLNL). The use of SAMR techniques permits a finer solution of the fields (resolving every small local charges separation), and consequently the extension of the simulations beyond the limits of the es-cPIF code (caused by the amplification of numerical errors for the strongly varying fields onto the static grid fixed). Furthermore, the inclusion of the code within SAMRAI turned the old serial code into a new parallel one, with a consequent reduction of execution times together with a more accurate particles sampling in a full 3D simulation domain.
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Codes