@article{almousa_gilligan_bourham_2016, title={Surface Ablation and Melting of Fusion Materials Simulated by Transient High Heat Flux Generated in an Electothermal Plasma Source}, volume={44}, ISSN={0093-3813 1939-9375}, url={http://dx.doi.org/10.1109/TPS.2016.2566445}, DOI={10.1109/tps.2016.2566445}, abstractNote={An electrothermal (ET) plasma source has been used to produce intense transient high heat flux to evaluate surface erosion and melting of plasma-facing materials. The source produces high heat flux relevant to expected conditions during disruption event in future large fusion devices. Surface vaporization has been evaluated for selected fusion-relevant materials under radiant energy deposition. Additional simulation included the effect of melting and splattering. Vapor and droplet formation and their associated shielding effect have been investigated in this paper to assess the difference between a developed boundary layer from only vapor or melt layer or the mixed vapor-melt layer with possible ejection of molten droplets away from the surface. Fully self-consistent erosion models are developed and implemented in the ET ETFLOW code in a new version ETFLOW-boundary layer to model the response of plasma-facing materials and their erosive behavior under transient ET plasma high heat fluxes closely similar to expected ones in future fusion large tokamaks.}, number={9}, journal={IEEE Transactions on Plasma Science}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Almousa, Nouf M. and Gilligan, John G. and Bourham, Mohamed}, year={2016}, month={Sep}, pages={1642–1648} } @article{gonzalez_gilligan_winfrey_bourham_2015, title={Generalized Scaling Laws of Plasma Parameters in Electrothermal Plasma Sources for Fusion Disruption Erosion and Hypervelocity Launch Applications}, volume={43}, ISSN={["1939-9375"]}, DOI={10.1109/tps.2015.2474835}, abstractNote={Generalized operational scaling laws have been developed for the peak plasma parameters at the exit of an electrothermal plasma capillary discharge. These parameters are the total ablated mass, plasma kinetic temperature, pressure, bulk velocity, and the radiant heat flux. The obtained scaling laws have particular coefficients depending on the material of the ablating liner inside the capillary source. The generalized scaling laws include the magnitude of the peak discharge current, material property, and the dimensions of the ablating sleeve. The values given by the scaling laws are compared with the ones calculated by the computational ElectroThermal Flow (ETFLOW) code and against the experimental data. The obtained results of the scaling laws have shown low error, especially the scaling laws of the kinetic temperature and the plasma exit velocity.}, number={10}, journal={IEEE TRANSACTIONS ON PLASMA SCIENCE}, author={Gonzalez, P. P. Vergara and Gilligan, John and Winfrey, Leigh and Bourham, Mohamed A.}, year={2015}, month={Oct}, pages={3645–3652} } @article{majumdar_gilligan_winfrey_bourham_2015, title={Scaling Laws of Bulk Plasma Parameters for a 1-D Flow through a Capillary with Extended Converging-Diverging Nozzle for Simulated Expansion into Fusion Reactor Chamber}, volume={34}, ISSN={["1572-9591"]}, DOI={10.1007/s10894-015-9899-2}, number={4}, journal={JOURNAL OF FUSION ENERGY}, author={Majumdar, Rudrodip and Gilligan, John G. and Winfrey, A. Leigh and Bourham, Mohamed A.}, year={2015}, month={Aug}, pages={905–910} } @article{majumdar_gilligan_winfrey_bourham_2014, title={Supersonic Flow Patterns from Electrothermal Plasma Source for Simulated Ablation and Aerosol Expansion Following a Fusion Disruption}, volume={33}, ISSN={["1572-9591"]}, DOI={10.1007/s10894-013-9635-8}, number={1}, journal={JOURNAL OF FUSION ENERGY}, author={Majumdar, Rudrodip and Gilligan, John G. and Winfrey, A. Leigh and Bourham, Mohamed A.}, year={2014}, month={Feb}, pages={25–31} } @article{winfrey_gilligan_bourham_2013, title={A Computational Study of a Capillary Discharge Pellet Accelerator Concept for Magnetic Fusion Fueling}, volume={32}, ISSN={["1572-9591"]}, DOI={10.1007/s10894-012-9549-x}, number={2}, journal={JOURNAL OF FUSION ENERGY}, author={Winfrey, A. Leigh and Gilligan, John G. and Bourham, Mohamed A.}, year={2013}, month={Apr}, pages={227–234} } @article{winfrey_abd al-halim_gilligan_saveliev_bourham_2012, title={A Study of Plasma Parameters in a Capillary Discharge With Calculations Using Ideal and Nonideal Plasma Models for Comparison With Experiment}, volume={40}, ISSN={["0093-3813"]}, DOI={10.1109/tps.2011.2179985}, abstractNote={A study of the plasma parameters in a capillary discharge was conducted using an experimental electrothermal plasma facility. The experimental results are compared to calculations using ideal and nonideal formulas of the Coulomb logarithm in the plasma electrical conductivity model to determine the nature of the plasma regime. Calculations are compared to the measured ablated mass, the measured electrical conductivity. Other calculated parameters are compared to results from similar and typical discharges. The measured ablated mass falls in between the ideal and nonideal calculations suggesting that the plasma is neither ideal nor nonideal; however, the linear fit of the experimental and calculated values shows divergence in the ideal calculations at higher peak currents. Measured plasma electrical conductivity is close to the ideal model predictions at lower values of the peak discharge current and approaches the nonideal model predictions at higher peak currents; the shape of the measured conductivity follows that of the nonideal model.}, number={3}, journal={IEEE TRANSACTIONS ON PLASMA SCIENCE}, author={Winfrey, A. Leigh and Abd Al-Halim, Mohamed A. and Gilligan, John G. and Saveliev, Alexei V. and Bourham, Mohamed A.}, year={2012}, month={Mar}, pages={843–852} } @article{winfrey_abd al-halim_saveliev_gilligan_bourham_2013, title={Enhanced Performance of Electrothermal Plasma Sources as Fusion Pellet Injection Drivers and Space Based Mini-Thrusters via Extension of a Flattop Discharge Current}, volume={32}, ISSN={["0164-0313"]}, DOI={10.1007/s10894-012-9578-5}, number={3}, journal={JOURNAL OF FUSION ENERGY}, author={Winfrey, A. Leigh and Abd Al-Halim, Mohamed A. and Saveliev, Alexei V. and Gilligan, John G. and Bourham, Mohamed A.}, year={2013}, month={Jun}, pages={371–377} } @inproceedings{winfrey_gilligan_bourham_2011, title={A comparative study of different low-Z liner materials in an ablation-dominated electrothermal mass accelerator for fusion fueling}, DOI={10.1109/sofe.2011.6052238}, abstractNote={A low-z ablation-dominated capillary with an ablation-free extension barrel is a concept that provides a plasma flow sufficient to propel fuel pellets into the tokamak fusion plasma chamber. The acceleration barrel is made from a non-ablating material to eliminate mixing the propelling plasma with any impurities evolving from the barrel ablation.}, booktitle={2011 IEEE/NPSS 24th Symposium on Fusion Engineering (SOFE)}, author={Winfrey, A. L. and Gilligan, J. G. and Bourham, Mohamed}, year={2011} } @article{winfrey_abd al-halim_gilligan_saveliev_bourham_2011, title={MODELING OF AN ABLATION-FREE ELECTROTHERMAL PLASMA PELLET ACCELERATOR}, volume={60}, ISSN={["1536-1055"]}, DOI={10.13182/fst60-480}, abstractNote={Abstract Electromagnetic and electrothermal launch devices can provide high acceleration and inject pellets with speeds in excess of 3 km/s for masses up to 3gm. However, the ablation of the bore adds impurities to the plasma. An ablation-free electrothermal pellet accelerator is a concept that utilizes an ablation-free capillary discharge in which a quartz capillary is coated with a nanocrystalline diamond film (NCD). The ablation-free capillary connects to an extension tube, which is also an ablation-free quartz tube coated with NCD that serves as the acceleration barrel. An ablation-free capillary discharge computer code has been developed to model plasma flow and acceleration of pellets for fusion fueling in magnetic fusion reactors. The code incorporates ideal and non-ideal conductivity models and has a set of governing equations for the capillary, the acceleration tube, and the pellet. The capillary generates the plasma from hydrogen/deuterium gas when the discharge current flows through the capillary. The pellet starts moving in the extension tube when the pressure of the plasma flow from the capillary reaches the release limit. The code results show an exit velocity of 2.7 km/s for a 20 mg deuterium pellet when using a capillary and barrel each 9 cm long where the source and barrel diameters are 0.4cm and 0.6cm, respectively, with a discharge current of 20 kA over a 300 both the capillary and the barrel to 12 cm increases the pellet exit velocity to 2.9 km/s, and a further increase to 18cm results in a 3.15km/s pellet exit velocity. Increasing the barrel length to 36 cm, while keeping the source length at 18 cm, results in an increase in the pellet velocity to 3.32 km/s. The pellet starts moving at 35 μs reaches 3.32 km/s in 100 this velocity until exiting the acceleration tube.}, number={2}, journal={FUSION SCIENCE AND TECHNOLOGY}, author={Winfrey, A. Leigh and Abd Al-Halim, Mohamed and Gilligan, John G. and Saveliev, Alexei V. and Bourham, Mohamed A.}, year={2011}, month={Aug}, pages={480–485} } @inproceedings{brent_felder_rajala_gilligan_lee_2001, title={New faculty 101: an orientation to the profession}, DOI={10.1109/fie.2001.964046}, abstractNote={In August 2000 the North Carolina State University College of Engineering (USA) with partial sponsorship from the SUCCEED Coalition organized and presented a one-week orientation workshop for new faculty members. The workshop goal was to equip new faculty members to become what Robert Boice calls "quick starters", who meet or exceed their institution's expectations for both research productivity and teaching effectiveness in their first one to two years. Two days were devoted to research program startup and management, two to effective teaching, and the final morning to managing time, integrating into campus culture, and earning tenure and promotion. The participants were unanimously and overwhelmingly positive in their responses following the workshop, and their enthusiasm has continued at gatherings and in surveys in the months that followed. This paper describes the workshop content and activities, summarizes follow-up support and assessment plans, and offers suggestions for planning and implementing similar programs.}, number={2001 October}, booktitle={2001 Frontiers in Education Conference Proceedings, Reno, NV, October 2001}, author={Brent, R. and Felder, R. M. and Rajala, S. A. and Gilligan, J. G. and Lee, G.}, year={2001} } @article{sharpe_merrill_petti_bourham_gilligan_2001, title={Modeling of particulate production in the SIRENS plasma disruption simulator}, volume={290}, ISSN={["0022-3115"]}, DOI={10.1016/S0022-3115(00)00550-X}, abstractNote={Modeling of the complex interplay among plasma physics, fluid mechanics, and aerosol dynamics is critical to providing a detailed understanding of the mechanisms responsible for particulate production from plasma–surface interaction in fusion devices. Plasma/fluid and aerosol models developed for analysis of disruption simulation experiments in the SIRENS high heat flux facility integrate the necessary mechanisms of plasma–material interaction, plasma and fluid flow, and particulate generation and transport. The model successfully predicts the size distribution of primary particulate generated in SIRENS disruption-induced material mobilization experiments.}, number={2001 Mar.}, journal={JOURNAL OF NUCLEAR MATERIALS}, author={Sharpe, JP and Merrill, BJ and Petti, DA and Bourham, MA and Gilligan, JG}, year={2001}, month={Mar}, pages={1128–1133} } @article{bourham_gilligan_1999, title={Augmentation and control of burn rates in plasma devices}, number={1999 May 10}, journal={Final Technical Report for the US Navy, Office of Naval Research. Contract #N00014-95-1-1221}, author={Bourham, M. A. and Gilligan, J. G.}, year={1999} } @book{bourham_gilligan_1999, title={Augmentation and control of burn rates in plasma devices: Final technical report}, number={1999 May 10}, journal={US Navy, Office of Naval Research, May 1999. Contract #N00014-95-1-1221}, author={Bourham, M. A. and Gilligan, J. G.}, year={1999} } @article{tucker_gilligan_1998, title={Effects of vapor shield expansion on vapor shield effectiveness and plasma gun efficiency}, volume={33}, DOI={10.13182/FST98-A22}, abstractNote={The vapor shield outward expansion rate can be shown to affect energy transport through the vapor shield, thereby influencing the vapor shield effectiveness. To more accurately determine the divertor plate erosion depth from a tokamak fusion reactor disruption or plasma gun sources, it is then necessary to include source plasma (beam) momentum transfer and beam mass deposition to the expanding vapor shield. Other factors such as incident heat flux and target Z value are shown to influence the vapor shield expansion rate as well. Code calculations show that increasing heat fluxes can increase the fraction of vapor shield kinetic energy and lower the fraction f of incident energy transported to the solid. Low-Z materials give higher kinetic energies as well but result in a higher f due to a lower specific heat. These results can also be applied to plasma gun technology to help increase its efficiency. In an electrothermal gun, the plasma expansion rate (rate at which vaporized material travels out of the gun) can cause differing plasma residence times and differing plasma temperatures as well. Determining the mechanisms that influence the vapor shield expansion rate and showing its sensitivity on f can give us a qualitative way of determining how changing parameters can influence plasma gun efficiency. Low-energy (<200 eV) disruption plasmas add much mass as well as momentum to a vapor shield. Mass addition can cause the vapor shield temperature and f to differ for a given incident heat flux and change the vapor shield expansion rate as well. Also, we find that deuterium's shielding effectiveness differs from carbon.}, number={2}, journal={Fusion Technology}, author={Tucker, E. and Gilligan, J.}, year={1998}, pages={118–129} } @article{sharpe_bourham_gilligan_1998, title={Generation and characterization of carbon particulate in disruption simulations}, volume={34}, ISSN={["0748-1896"]}, DOI={10.13182/fst98-a11963685}, abstractNote={The SIRENS high heat flux facility at NCSU has been used to generate particulate representative of material mobilized during a hard disruption in a fusion reactor. The electrothermal (ET) plasma so...}, number={3}, journal={FUSION TECHNOLOGY}, author={Sharpe, JP and Bourham, M and Gilligan, JG}, year={1998}, month={Nov}, pages={634–639} } @book{verghese_gilligan_1998, title={Nuclear engineering education sourcebook 1998}, publisher={Raleigh, NC: American Nuclear Society, Education and Training Division}, author={Verghese, K. and Gilligan, J.}, year={1998} } @article{bourham_gilligan_oberle_1997, title={Analysis of solid propellant combustion behavior under electrothermal plasma injection for ETC launchers}, volume={33}, ISSN={["0018-9464"]}, DOI={10.1109/20.559969}, abstractNote={Enhanced burn rates of solid propellants through plasma erosion has been studied showing evidence of increased burn rate with injection of electrothermal plasmas into the propellant. These experiments are designed to evaluate the effectiveness of maximizing energy versus momentum transport, and the influence of geometry on the burn rates of the JA-2 solid granular propellant. A series of experiments has shown evidence of enhanced burn rate at pressures between 55 and 90 MPa (8,000 and 12,000 psi, respectively) over 400 ps pulse length. A 20 to 40% enhancement in the burn rates has been observed when plasma is injected parallel to the surface of the propellant. When plasma is injected normal to the surface, the burn rate increases by about a factor of three. A set of experiments has been designed to measure the burn rates when the electrothermal plasma is injected at various angles, from 0/spl deg/ to 90/spl deg/, to the surface of the propellant. Experiments were conducted at a constant input energy of 5 kJ/spl plusmn/2% to the electrothermal plasma source and constant base pressure of 15 Torr, which provides a 12,300 psi plasma pressure at the source exit close to the surface of the propellant. Results indicate increased burn rates with increased angle of injection. Optical emission spectroscopy measurements revealed a decrease in plasma temperature, at the plasma-propellant interface, with increased angle of injection.}, number={1}, journal={IEEE TRANSACTIONS ON MAGNETICS}, author={Bourham, MA and Gilligan, JG and Oberle, WF}, year={1997}, month={Jan}, pages={278–283} } @inbook{sharpe_bourham_gilligan_1997, title={Experimental investigation of disruption-induced aerosol mobilization in accident scenarios of ITER}, volume={1}, booktitle={17th IEEE/NPSS Symposium Fusion Engineering: San Diego, California, October 6-10, 1997}, publisher={Piscataway, NJ: IEEE}, author={Sharpe, J. P. and Bourham, M. A. and Gilligan, J. G.}, year={1997}, pages={153–156} } @article{tucker_gilligan_1997, title={Model of turbulent mixing of species, momentum, and energy in a vapor shield plasma}, volume={32}, ISSN={["0748-1896"]}, DOI={10.13182/FST97-A19895}, abstractNote={Evidence suggests that turbulent mixing may affect the energy transport through the vapor shield (VS) formed during a tokamak disruption. The VS is first found to be very unstable according to the Rayleigh-Taylor stability criteria. Adding beam mass to the vaporized material and then mixing of the entire VS is found to cause a significant increase in energy transport through the VS for fusion reactor disruption-relevant energy beams. Mixing the VS for electrothermal gun-relevant energy beams can also affect the energy transport rate, depending on the source species used.}, number={2}, journal={FUSION TECHNOLOGY}, author={Tucker, EC and Gilligan, JG}, year={1997}, month={Sep}, pages={253–262} } @inproceedings{bourham_gilligan_doster_orton_tucker_1997, title={Simulation of plasma-surface interactions in electrothermal-chemical devices: progress on the 2-D code TURFIRE}, volume={1}, number={1997}, booktitle={Proc. 34th JANNAF Combustion Meeting, CPIA Publications 662, West Palm Beach, FL, 27-31 October 1997}, publisher={CPIA, Chemical Propulsion Information Agency}, author={Bourham, M. A. and Gilligan, J. G. and Doster, J. M. and Orton, N. P. and Tucker, E. C.}, year={1997}, pages={57–63} }