SETUP OF AN INDUCTIVELY–HEATED PLASMA GENERATOR AND DIAGNO STICS TO BUILD AHYBRID PLASMA SIMULATION FACILITY FOR COMPLEX SPACE ENVIRO NMENT INVESTIGA-TIONS. M. Dropmann1,2, C. Gomringer1,2, H. Koch1,2, S. Peters1,2, G. Herdrich1,2, M. Cook1, J. Schmoke1, R. Laufer-1,2, S. Matthews1, T. W. Hyde1, 1CASPER (Center for Astrophysics, Space Physics and Engineering Research), OneBear Place 97310, Baylor University, Waco, TX 76798,2Institute of Space Systems (IRS), Universitaet Stuttgart,Pfaffenwaldring 31, 70569 Stuttgart, Germany (Rene_Laufer@baylor.edu; Truell_Hyde@baylor.edu)

Introduction: Plasma is the most common state inthe universe; over 99% of the visible matter exists inthe plasma state. As a result, it is essential to useground test facilities for basic investigations to gatherinformation about conditions in space before sendingobjects into it. Existing techniques cover only a specif-

of less than 0.5 g/s. The pressure in the IPG6-S facilityis several 100 Pa during operation, while the IPG6-Bfacility is capable of pressures as low as 2 Pa. Workinggases used to date include air and argon. For future op-eration, hydrogen, helium, oxygen and carbon dioxidewill also be considered.

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walls the reactants are progressively removed from thegas phase, establishing a decreasing species concentra-tion profile over the length of the side-arm tube. Given these subsystems, the IPG6-B will be able tocreate a wide range of space and terrestrial environ-ments.

Diagnostics:Diagnostics are an important compon-ent for experimental research. Dealing with the specificfield of plasma it is necessary to have specially de-signed diagnostics equipment, which provide the re-quired information during experiments. In a first stepthree diagnostic systems for IPG6-B are currently indevelopment.

Calorimeter: In order to measure the total plasmapower of the IPG6-B a cavity calorimeter has been de-veloped consisting of a water-cooled copper cone. Theplasma enters the cone and exchanges energy with thecopper walls. Based on the increase of cooling watertemperature, cooling water flow rate and plasma massflow rate, the plasma power can be calculated, once en-ergy losses have been considered.

Oxygen Sensor: VacuSEN is a miniaturized uniquesensor system that was developed based on the spaceexperiment FIPEX on ISS. It enables measurements ofboth the molecular and atomic oxygen concentrationsinside the plasma chamber. The working principle is anamperometric solid electrolyte sensor that is able tomeasure a partial pressure down to 1·10-6 mbar pO2.

Due to the space driven miniaturization and refer-ence free measurement principle, the robust ceramicsensor can be used for direct time resolved in-situmeasurements.

Pitot Probe: In order to gather data about the pres-sure inside the vacuum chamber, which is influencedby the emitted plasma, a pitot probe is being developedfor the IPG6-B. For the purpose of measuring in andnear the extremely hot plasma stream, the pitot probe isa miniaturized and water-cooled pressure measurementinstrument which can be attached at different positions.This enables the measurement of pressure profiles andhelps to characterize the plasma and the conditions in-side the vacuum chamber.

Potential Applications: IPG6-B offers many op-portunities for investigations. At CASPER the follow-ing applications are of main interest.

Catalysis: Using the side-arm technology and theVacuSEN System gives the opportunity to collect datadetermining the oxygen amount along the side-arm. Byplacing a sample into the tube the change in oxygenconcentration before and after the probe can be meas-ured. Depending on the concentration, catalytic surfaceproperties of the sample material can be calculated.

Atmospheric Entry: One of the most important in-vestigations in human and unmanned space exploration

is the field of atmospheric entry. Using heat shields,which resist the heat flux during entry, is vital for thesuccess of any mission. Being capable of using variousgases, even chemically reactive ones, the IPG6 test fa-cility provides the opportunity to generate a high-enthalpy plasma of various compositions to simulateentries into different atmospheres eg. Earth and Mars.

Satellite Hardware: The large vacuum chamberand side-arm subsystem at IPG6-B are important assetsto create low plasma densities, assuming a decrease ofthe plasma density with greater distance from theplasma source. The reproduction of plasma conditions,that have relevance for both aerothermodynamics andplasma environments in space, allows investigation ofambient plasma properties that are common in differ-ent orbits, eg. the Lower Earth Orbit (LEO), that is ofinterest for investigations of effects on satellite hard-ware.

Dusty Plasma: The Moon as well as comets and as-teroids are promising targets for future exploration.The Moon has an extremely thin atmosphere of 1·104

molecules/m3 during lunar day and 2·105 molecules/m3

during lunar night [3]. The solar wind and impacts hitthe surface almost unharmed, creating a hazardous en-vironment for human missions with dust particle velo-cities up to of 2.7 km/s and a mean size of 60 to 80 µmin diameter. Plasma velocities of 300 to 700 km/s arecommon. Comets in the vicinity of the sun developdust and plasma tails, at first coupled due to particle-molecule collisions in the tail before spreading due tosolar radiation pressure. Nucleus ejecta velocities varyfrom 0.4 to 0.7 km/s [4]. The micro-meteoroids arelinked with the plasma tail and thus have about thesame velocity of 10 to 100 km/s as observed fromEarth [5].

Terrestrial Applications: A final potential applica-tion of the IPG6-B test facility is the simulation of heatfluxes and dust impact at the divertor plate of tokamaknuclear fusion reactors. In this area there are still un-solved material issues, which need to be addressed fornext step fusion reactors. IPGs are capable of creatingthe required high enthalpy hydrogen/helium plasmaswhich are found near the divertor plate. FurtherCASPER’s Light Gas Gun (LGG), which will be at-tached to the test facility, can be used to accelerate dustparticles to relevant velocities.

References:[1] Carmona-Reyes J. et al. (2004)LPS XXXV, Ab-

stract #1019. [2] Peters S. (2012)Diploma Thesis.[3] Heiken G. H., Animan D. T. and French B. M.(1991) Lunar Source Book. [4] Wychoff, S. (1983)Comets 3-84. [5] Grün E., Baguhl M., Svedhem H. andZook H. A. (2001) Interplanetary Dust 295.

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