VORPAL
Encyclopedia
VORPAL is a computational plasma
framework that can predict the dynamics of
electromagnetic
systems, plasmas, and
rarefied as well as dense gas
es. VORPAL is used for
modeling vacuum electronics, photonic devices, laser wake-field acceleration
, plasma thrusters, fusion
plasmas, and
multipactor effect
s in Superconducting RF cavities.
Originally developed by the Plasma and Beam Physics Group at
the University of
Colorado, VORPAL is
currently developed and marketed by Tech-X
Corporation.
VORPAL is highly flexible. It is arbitrary dimensional,
meaning that it can be run in one, two, or three dimensions.
Plasma in VORPAL can be represented by a fluid or
kinetically using the PIC
algorithm
(with a continuum/Vlasov representation in development). It
can be run in full electromagnetic mode or with an
electrostatically computed field. The fields and particles
can be bounded by arbitrarily shaped structures, including
conductors, particle absorbers, reflectors, and many more.
The computational domain can be periodic or mimic boundaries
at infinity via PML (Perfectly Matched Layer
) boundary
conditions. Particles can also interact through collisions
as in Direct simulation Monte Carlo
(DSMC).
The implementations for the basic collisional processes are
provided by the TxPhysics cross-platform library of
computational modules. These include models for impact
ionization of neutral gases by electrons and ions and
field-induced tunneling ionization of atoms. VORPAL can
also, through use of TxPhysics, include the ion range and
stopping power in solids, ion-induced electron yield from
solids, and secondary electron yields.
VORPAL can be run from its GUI
interface or from the
command line. The serial version of VORPAL runs on single
processor workstations. The parallel version of VORPAL runs
on systems that support the Message Passing Interface
(MPI
). Input to VORPAL is made
through use of XML
-like files used to create simulation
objects. (A python too, txpp.py, can be used to generate
input files allowing users to set up their simulations with
math functions, variable substitutions, and macros.
VORPAL
outputs data in HDF5 (Hierarchical Data Format
) that
is VizSchema compliant.
VORPAL output files can be viewed via VorpalView, the GUI
tool for visualizing plots of particle data, field data, and
simulation geometry that is included in VORPAL. VorpalView
is written in IDL
and runs on the
free IDL virtual machine (versions 7.0.3 or greater). VORPAL
output files may also be viewed with other visualization
tools such as VisIt
.
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
framework that can predict the dynamics of
electromagnetic
Electromagnetism
Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
systems, plasmas, and
rarefied as well as dense gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
es. VORPAL is used for
modeling vacuum electronics, photonic devices, laser wake-field acceleration
Plasma acceleration
Plasma Wakefield acceleration is a technique for accelerating charged particles, such as electrons, positrons and ions, using an electric field associated with an electron plasma wave. The wave is created either using electron pulses or through the passage of a very brief laser pulses, a technique...
, plasma thrusters, fusion
Fusion power
Fusion power is the power generated by nuclear fusion processes. In fusion reactions two light atomic nuclei fuse together to form a heavier nucleus . In doing so they release a comparatively large amount of energy arising from the binding energy due to the strong nuclear force which is manifested...
plasmas, and
multipactor effect
Multipactor effect
The multipactor effect is a phenomenon in radio frequency amplifier vacuum tubes and waveguides, where, under certain conditions, secondary electron emission in resonance with an alternating electric field leads to exponential electron multiplication, possibly damaging and even destroying the RF...
s in Superconducting RF cavities.
Originally developed by the Plasma and Beam Physics Group at
the University of
Colorado, VORPAL is
currently developed and marketed by Tech-X
Corporation.
VORPAL is highly flexible. It is arbitrary dimensional,
meaning that it can be run in one, two, or three dimensions.
Plasma in VORPAL can be represented by a fluid or
kinetically using the PIC
Particle-in-cell
The Particle-in-Cell method refers to a technique used to solve a certain class of partial differential equations. In this method, individual particles in a Lagrangian frame are tracked in continuous phase space, whereas moments of the distribution such as densities and currents are computed...
algorithm
(with a continuum/Vlasov representation in development). It
can be run in full electromagnetic mode or with an
electrostatically computed field. The fields and particles
can be bounded by arbitrarily shaped structures, including
conductors, particle absorbers, reflectors, and many more.
The computational domain can be periodic or mimic boundaries
at infinity via PML (Perfectly Matched Layer
Perfectly matched layer
A perfectly matched layer is an artificial absorbing layer for wave equations, commonly used to truncate computational regions in numerical methods to simulate problems with open boundaries, especially in the FDTD and FEM methods...
) boundary
conditions. Particles can also interact through collisions
as in Direct simulation Monte Carlo
Direct simulation Monte Carlo
Direct Simulation Monte Carlo method uses probabilistic simulation to solve the Boltzmann equation for finite Knudsen number fluid flows....
(DSMC).
The implementations for the basic collisional processes are
provided by the TxPhysics cross-platform library of
computational modules. These include models for impact
ionization of neutral gases by electrons and ions and
field-induced tunneling ionization of atoms. VORPAL can
also, through use of TxPhysics, include the ion range and
stopping power in solids, ion-induced electron yield from
solids, and secondary electron yields.
VORPAL can be run from its GUI
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
interface or from the
command line. The serial version of VORPAL runs on single
processor workstations. The parallel version of VORPAL runs
on systems that support the Message Passing Interface
(MPI
Message Passing Interface
Message Passing Interface is a standardized and portable message-passing system designed by a group of researchers from academia and industry to function on a wide variety of parallel computers...
). Input to VORPAL is made
through use of XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
-like files used to create simulation
objects. (A python too, txpp.py, can be used to generate
input files allowing users to set up their simulations with
math functions, variable substitutions, and macros.
VORPAL
outputs data in HDF5 (Hierarchical Data Format
Hierarchical Data Format
Hierarchical Data Format is the name of a set of file formats and libraries designed to store and organize large amounts of numerical data...
) that
is VizSchema compliant.
VORPAL output files can be viewed via VorpalView, the GUI
tool for visualizing plots of particle data, field data, and
simulation geometry that is included in VORPAL. VorpalView
is written in IDL
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
and runs on the
free IDL virtual machine (versions 7.0.3 or greater). VORPAL
output files may also be viewed with other visualization
tools such as VisIt
VisIt
VisIt is an open source interactive parallel visualization and graphical analysis tool for viewing scientific data. It can be used to visualize scalar and vector fields defined on 2D and 3D structured and unstructured meshes...
.