Ion Cyclotron Resonant Heating (ICRH) System Used on the Tandem Mirror Experiment-Upgrade (TMX-U).

Ion Cyclotron Resonant Heating (ICRH) System Used on the Tandem Mirror Experiment-Upgrade (TMX-U). PDF Author:
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Languages : en
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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.

Ion Cyclotron Resonant Heating (ICRH) System Used on the Tandem Mirror Experiment-Upgrade (TMX-U).

Ion Cyclotron Resonant Heating (ICRH) System Used on the Tandem Mirror Experiment-Upgrade (TMX-U). PDF Author:
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Languages : en
Pages :

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Book 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.

Use of ICRH for Startup and Initial Heating of the TMX-U Central Cell

Use of ICRH for Startup and Initial Heating of the TMX-U Central Cell PDF Author:
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Languages : en
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Ion cyclotron resonance heating (ICRH) was evaluated and it was found to be satisfactory for use in establishing the conditions necessary to form a thermal barrier in TMX-upgrade (TMX-U). We discuss the constraints that must be satisfied in order to maintain a plasma, and outline a complete startup scenario that ends with the plasma at design parameters. The detailed discussions in this report concentrate on those parts of startup where ICRH is necessary. The ability of ICRH to couple power into a plasma at the fundamental ion cyclotron resonance, w/sub ci/, is determined from experiments with a half-turn loop antenna in the Phaedrus tandem mirror central cell. From these experiments, we get the empirical scaling that shows power deposited in the plasma is proportional to the plasma density.

Ion Cyclotron Resonant Heating Slot Antenna for the Tandem Mirror Experiment-Upgrade

Ion Cyclotron Resonant Heating Slot Antenna for the Tandem Mirror Experiment-Upgrade PDF Author:
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Languages : en
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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.

Measurements of Radial Profiles of Ion Cyclotron Resonance Heating on the Tandem Mirror Experiment-upgrade

Measurements of Radial Profiles of Ion Cyclotron Resonance Heating on the Tandem Mirror Experiment-upgrade PDF Author: Steven Falabella
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Languages : en
Pages : 342

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Tandem Mirror Experiment Upgrade (TMX-U) Overview-recent Events

Tandem Mirror Experiment Upgrade (TMX-U) Overview-recent Events PDF Author:
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Languages : en
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Since its construction and commissioning was completed in the winter of 1981, the Tandem Mirror Experiment Upgrade (TMX-U) has been conducting tandem mirror thermal barrier experiments. The work, following the fall of 1983 when strong plugging with thermal barriers was achieved, has been directed toward controlling radial transport and forming thermal barriers with high density and Beta. This paper describes the overall engineering component of these efforts. Major changes to the machine have included vacuum improvements, changes to the Electron and Ion Cyclotron Resonance Heating systems (ECRH and ICRH), and the installation of a Plasma Potential Control system (PPC) for radial transport reduction. TMX-U operates an extensive diagnostics system that acquires data from 21 types of diagnostic instruments with more than 600 channels, in addition to 246 machine parameters. The changes and additions will be presented. The closing section of this paper will describe the initial study work for a proposed TMX-U octupole configured machine.

Measurements of Radial Profiles of Ion Cyclotron Resonance Heating on the Tandem Mirror Experiment-Upgrade

Measurements of Radial Profiles of Ion Cyclotron Resonance Heating on the Tandem Mirror Experiment-Upgrade PDF Author:
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Languages : en
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A small Radial Energy Analyzer (REA) was used on the Tandem Mirror Experiment-Upgrade (TMX-U), at Lawerence Livermore National Laboratory, to investigate the radial profiles of ion temperature, density, and plasma potential during Ion Cyclotron Resonance Heating (ICRH). The probe has been inserted into the central-cell plasma at temperatures of 200 eV and densities of 3 x 1012cm/sup /minus 3// without damage to the probe, or major degradation of the plasma. This analyzer has indicated an increase in ion temperature from near 20 eV before ICRH to near 150 eV during ICRH, with about 60 kW of broadcast power. The REA measurements were cross-checked against other diagnostics on TMX-U and found to be consistent. The ion density measurement was compared to the line-density measured by microwave interferometry and found to agree within 10 to 20%. A radial intergral of n/sub i/T/sub i/ as measured by the REA shows good agreement with the diamagnetic loop measurement of plasma energy. The radial density profile is observed to broaden during the RF heating pulses, without inducing additional radial losses in the core plasma. The radial profile of plasma is seen to vary from axially peaked, to nearly flat as the plasma conditions carried over the series of experiments. To relate the increase in ion temperature to power absorbed by the plasma, a power balance as a function of radius was performed. The RF power absorbed is set equal to the sum of the losses during ICRH, minus those without ICRH. This method accounts for more than 70% of the broadcast power using a simple power balance model. The measured radial profile of the RF heating was compared to the calculations of two codes, ANTENA and GARFIELD, to test their effectiveness as predictors of power absorption profiles for TMX-U. 62 refs., 63 figs., 7 tabs.

TMX-U (Tandem Mirror Experiment Upgrade) ECRH (Electron Cyclotron Resonant Heating) System Operations Summary

TMX-U (Tandem Mirror Experiment Upgrade) ECRH (Electron Cyclotron Resonant Heating) System Operations Summary PDF Author:
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Languages : en
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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.

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

Changes and Developments in Electron Cyclotron Resonant Heating (ECRH) on the Tandem Mirror Experiment Upgrade (TMX-U). PDF Author:
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Languages : en
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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.

Ion Cyclotron Radio Frequency Systems and Performance on the Tandem Mirror Experiment-upgrade (TMX-U).

Ion Cyclotron Radio Frequency Systems and Performance on the Tandem Mirror Experiment-upgrade (TMX-U). PDF Author:
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Languages : en
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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.

Electron Cyclotron Resonance Heating (ECRH) in the TMX-Upgrade Tandem-mirror Experiment

Electron Cyclotron Resonance Heating (ECRH) in the TMX-Upgrade Tandem-mirror Experiment PDF Author:
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Languages : en
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Results are described of engineering tests of operation of two gyrotrons from one power supply, tests of waveguide components and antennae, antenna design, and the x-ray shielding concept. Finally, we describe considerations of interaction with other system components.