Project Contract:

Principal Investigator:
Lubos Brieda (540-449-5826)

Title:
Visual Analysis of a Simulated Plasma Plume and its Interaction with the Deep Space 1 Spacecraft

Background:
Electric Propulsion (EP) thrusters produce low thrust and thus must be operated for extensive time periods to generate the desired change in velocity, D V. The prolonged presence of the thruster plume is responsible for new design challenges, since the charged particles making up the plume can backflow on the spacecraft and contaminate the sensitive on-board electronics. Furthermore, grid erosion, caused by sputtering of the grid material upon collision with the propellant, is the main factor limiting a useful life of an EP thruster. These effects are however slow to manifest and thus very expensive to discover using vacuum tanks tests. A computer plasma simulation relies on the basic laws of plasma physics to calculate the flow properties for a specified system. Thus, it enables a faster and cheaper design-to-build cycle, since new hardware does not need to be build once design parameters are changed, and results can be obtained in several hours, instead of weeks.

Progress (as of 03/09/2003)
My undergraduate research consists of working with the other members of the Computational Advanced Propulsion Lab (Cap Lab) on simulating plasma for a variety of surface geometry conditions. Currently, the input conditions are entered using analytical expressions, but the ongoing work consists of generating a more universal code. This code is being developed as a joint project with MIT, under the sponsorhip of the Air Force Research Labs. The code will be able to read in a geometry definition file with the associated potential values, solve the electric field and perfom the simulation.

Furthermore, I am developing the Cap Lab Virtual Testing Environment, or capVTE. capVTE is a cross-platform visualization software, which uses the Visualization Toolkit for its object rendering. The objective of the program is to create an immersed visualization platform, allowing the user to study data on both a workstation and in the CAVE. Currently, it is possible to export .iv files which can then be explored in the CAVE using Diversifly. However, after completion, capVTE will directly interact with the CAVE. This will allow the user to adjust the visualization parameters from the CAVE by using the wand interface. Completion of the fully immersed version of capVTE is however outside the scope of this project.

Objectives:
The main objectives of the project are to:

• Generate an easy to understand multimedia presentation outlining the physical models used in computer plasma simulation.
• Use Tecplot and capVTE to explore the data from a simulation of the Deep Space 1 thruster. The two software packages will be explored and their respective strengths will be compared. The electric potential and charge density will be examined. The time-varying velocity distribution of the emmited ions will be animated.
• Discuss how inter-laboratora collaboration can be achieved using the CAVE Collaborative Toolkit, and how a similar interface will be incorporated into capVTE.

Tools:
The data analysis will be performed using Tecplot and capVTE. The supporting software will include the Diverse package, and a VRML web pluggin (such as vrweb). Animation of the vector field will be captured using a screen-capture software, but the specific software has not been identified yet.