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MTX (Microwave Tokamak Experiment) plasma diagnostic system

Description: In this paper, a general overview of the MTX plasma diagnostics system is given. This includes a description of the MTX machine configuration and the overall facility layout. The data acquisition system and techniques for diagnostic signal transmission are also discussed. In addition, the diagnostic instruments planned for both an initial ohmic-heating set and a second FEL-heating set are described. The expected range of plasma parameters along with the planned plasma measurements will be reviewed. 7 refs., 5 figs.
Date: October 7, 1987
Creator: Rice, B.W.; Hooper, E.B. & Brooksby, C.A.
Partner: UNT Libraries Government Documents Department

TMX-U (Tandem Mirror Experiment Upgrade) ECRH (Electron Cyclotron Resonant Heating) system operations summary

Description: The TMX-U ECRH System underwent many extensive changes during the last two years of physics operations. These changes included extensive use of fiber optics and computer control to add flexibility to the system and eliminate noise problems, upgrades to Varian Model VGA-8050M long pulse gyrotron tubes, the addition of gyrotron anode-modulation for better control of individual gyrotrons, and the installation of a fifth gyrotron socket that was used to simultaneously heat both the east and west inner 10 KG locations. This paper discusses the different modifications made to the system and their effects on the overall performance of the entire ECRH system. The paper also discusses the system as it presently exists and possible modifications that would be made if the future modifications were to be performed. 3 refs., 2 figs.
Date: October 7, 1987
Creator: Heefner, J.W.; Brooksby, C.A.; Lauze, R.R. & Karsner, P.G.
Partner: UNT Libraries Government Documents Department

Ion cyclotron resonant heating 2 x 170/sup 0/ loop antenna for the Tandem Mirror Experiment-Upgrade

Description: This paper reviews the mechanical design and improvements that have taken place on the loop type ion cyclotron resonance heating (ICRH) antennas that are located in the center cell region of the Tandem Mirror Experiment-Upgrade (TMX-U).
Date: November 14, 1985
Creator: Brooksby, C.A.; Ferguson, S.W.; Molvik, A.W. & Barter, J.
Partner: UNT Libraries Government Documents Department

Ion Cyclotron Resonant Heating slot antenna for the Tandem Mirror Experiment-Upgrade

Description: The Ion Cyclotron Resonant Heating (ICRH) slot antenna has been a part of the ion and electron plasma heating system in the central cell region of the Tandem Mirror Experiment-Upgrade (TMX-U). This paper presents the mechanical design and arrangement of the antenna, coax feed lines, feedthroughs, and matching network for the slot antenna.
Date: November 14, 1985
Creator: Brooksby, C.A.; Calderson, M.O.; Cummins, W.F.; Ferguson, S.W. & Williamson, V.L.
Partner: UNT Libraries Government Documents Department

Concepts and development of drift pumping for the Tandem Mirror Experiment-Upgrade (TMX-U)

Description: Low-energy ions trapped in the thermal barrier region of the TMX-U plasma cause a potential reduction which results in increased scattering and less thermal isolation between regions of the plasma. A method of removing these ions using magnetic field perturbations at the ion drift frequency has been developed. The concepts of ''drift pumping'' and hardware development are described in this paper. 5 refs., 7 figs.
Date: November 11, 1985
Creator: Kane, R.J.; Pedrotti, L.R.; Brooksby, C.A.; Cummins, W.F.; Jackson, M.C.; Poulsen, P. et al.
Partner: UNT Libraries Government Documents Department

A HIGH CURRENT, HIGH VOLTAGE SOLID-STATE PULSE GENERATOR FOR THE NIF PLASMA ELECTRODE POCKELS CELL

Description: A high current, high voltage, all solid-state pulse modulator has been developed for use in the Plasma Electrode Pockels Cell (PEPC) subsystem in the National Ignition Facility. The MOSFET-switched pulse generator, designed to be a more capable plug-in replacement for the thyratron-switched units currently deployed in NIF, offers unprecedented capabilities including burst-mode operation, pulse width agility and a steady-state pulse repetition frequency exceeding 1 Hz. Capable of delivering requisite fast risetime, 17 kV flattop pulses into a 6 {Omega} load, the pulser employs a modular architecture characteristic of the inductive adder technology, pioneered at LLNL for use in acceleration applications, which keeps primary voltages low (and well within the capabilities of existing FET technology), reduces fabrication costs and is amenable to rapid assembly and quick field repairs.
Date: July 27, 2007
Creator: Arnold, P A; Barbosa, F; Cook, E G; Hickman, B C; Akana, G L & Brooksby, C A
Partner: UNT Libraries Government Documents Department

Ion cyclotron radio frequency systems and performance on the tandem mirror experiment-upgrade (TMX-U)

Description: High power ion cyclotron radio frequency (ICRF) systems are now gaining greater attention than before as prime driver ion heating systems. Lawrence Livermore National Laboratory (LLNL) has installed a 200 kW high frequency (HF) transmitter system on its Tandem Mirror Experiment-Upgrade (TMX-U). This paper describes the system, antenna, controls, and monitoring apparatus. The transmitter operates into a high Q antenna installed in the central cell region of the experiment. It incorporates a dual-port feedback system to automatically adjust the transmitter's output power and allow the maximum consistent with the plasma loading of the antenna. Special techniques have been used to measure, in real-time, the dynamically changing loading values presented by the plasma. From the measurements, the antenna impedance can be optimized for specified plasma density.
Date: December 1, 1983
Creator: Moore, T.L.; Molvik, A.W.; Cummins, W.F.; Pedrotti, L.R.; Henderson, A.L.; Karsner, P.G. et al.
Partner: UNT Libraries Government Documents Department

Ion Cyclotron Resonant Heating (ICRH) system used on the Tandem Mirror Experiment-Upgrade (TMX-U)

Description: Ion Cyclotron Resonant Heating (ICRH) is part of the plasma heating system used on the TMX-U experiment. Radio frequency (RF) energy is injected into the TMX-U plasma at a frequency near the fundamental ion resonance (2 to 5 MHz). The RF fields impart high velocities to the ions in a direction perpendicular to the TMX-U magnetic field. Particle collision then converts this perpendicular heating to uniform plasma heating. This paper describes the various aspects of the ICRH system: antennas, power supplies, computer control, and data acquisition. 4 refs., 10 figs.
Date: November 11, 1985
Creator: Ferguson, S.W.; Maxwell, T.M.; Antelman, D.R.; Scofield, D.W.; Brooksby, C.A.; Karsner, P.G. et al.
Partner: UNT Libraries Government Documents Department

Changes and developments in Electron Cyclotron Resonant Heating (ECRH) on the Tandem Mirror Experiment Upgrade (TMX-U)

Description: This paper will describe changes to the previously reported Electron Cyclotron Resonant Heating (ECRH) circular waveguide systems that deliver power to the Tandem Mirror Experiment Upgrade (TMX-U) machine. Four gyrotrons and associated waveguide systems, operating at 28-GHz and 200 kW each, helped establish electrostatic plugging in the end cells of TMX-U. A fifth gyrotron has been installed to power two resonant locations in the end plugs. This system and the pair of 10 kG heaters now use a slot radiator to obtain a more uniform coverage of the plasma. In addition, four 18-GHz ECRH systems have been added to the machine. 3 refs., 7 figs.
Date: November 14, 1985
Creator: Anderson, A.T.; Brooksby, C.A.; Calderon, M.O.; Ellis, R.; Felker, B.; Horton, R.D. et al.
Partner: UNT Libraries Government Documents Department

Halo recycler for the Tandem Mirror Experiment Upgrade

Description: The halow recycler is a mechanical device on the Tandem Mirror Experiment Upgrade (TMX-U) that is designed to increase the density at the plasma edge providing enhanced shielding of the core plasma from background neutrals. Each recycler body, which consists of coaxial annular cylinders and a adjacent plenum closely follows the magnetic flux tubes in the transition region of TMX-U. Each plenum is provided with gas feed and pressure measurement systems as well as Langmuir probes. This paper describes the design, fabrication, installation, and operation of these devices.
Date: November 14, 1985
Creator: Brooksby, C.A.; Allen, S.L.; Pedrotti, L.R.; Simonen, T.C.; Wood, B.E.; Hsu, W.L. et al.
Partner: UNT Libraries Government Documents Department

Solid-State Modulators for RF And Fast Kickers

Description: As the switching capabilities of solid-state devices increase, these devices are being incorporated into modulator designs for high voltage accelerator applications. Solid-state modulators based on inductive adder circuit topology have demonstrated great versatility with regard to pulse width and pulse repetition rate while maintaining fast pulse rise and fall times. Additionally, these modulators are capable of being scaled to higher output voltage and power levels. An explanation of the basic circuit operation will be presented as well as test data of several different hardware systems.
Date: March 14, 2006
Creator: Cook, E. G.; Akana, G. L.; Gower, E. J.; Hawkins, S. A.; Hickman, B. C.; Brooksby, C. A. et al.
Partner: UNT Libraries Government Documents Department