Download or read book Ion Cyclotron Radio Frequency Systems and Performance on the Tandem Mirror Experiment upgrade TMX U written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Ion Cyclotron Resonant Heating ICRH System Used on the Tandem Mirror Experiment Upgrade TMX U written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1986 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tandem Mirror Experiment Upgrade TMX U Overview recent Events written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Fusion Energy Update written by and published by . This book was released on 1983 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of Radial Profiles of Ion Cyclotron Resonance Heating on the Tandem Mirror Experiment upgrade written by Steven Falabella and published by . This book was released on 1988 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1984 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes all works deriving from DOE, other related government-sponsored information and foreign nonnuclear information.
Download or read book TMX U Tandem Mirror Experiment Upgrade ECRH Electron Cyclotron Resonant Heating System Operations Summary written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Measurements of Radial Profiles of Ion Cyclotron Resonance Heating on the Tandem Mirror Experiment Upgrade written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Microstability of the TMX Tandem Mirror Experiments written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the tandem mirror device, an efficient source of warm ions, the central cell, is available for stabilization of ion loss-cone instabilities. These instabilities previously limited ion confinement in single-cell mirror experiments. In the simple tandem mirror device, TMX, the drift cyclotron loss-cone (DCLC) mode was stabilized by plasma flow from the central cell into the end cell. However, to enhance the central-cell confinement and provide MHD stability, neutral beams were injected perpendicular to the magnetic field, which resulted in the excitation in the end cell of the Alfven ion-cyclotron (AIC) instability driven by plasma pressure and velocity distribution anisotropy. In the thermal-barrier experiment, TMX-U, the end-cell beams were injected at a 45° angle to the magnetic field to produce a sloshing-ion distribution, which is required to form the thermal barrier and the plugging potential. Ion distributions created by oblique injection were stable to the AIC mode and to the midplane (minimum magnetic field location) DCLC mode. However, an ion loss-cone instability remained at an axial location just outside the outboard peak of the sloshing-ion axial density profile, which is the density peak closest to the end wall. This mode can enhance the sloshing-ion loss rate, particularly at the lower levels of electron-cyclotron resonance heating (ECRH) used to form the thermal barrier. The stability to ion-cyclotron modes is critical to the performance of tandem mirrors and to designs for a mirror-based, high-fluence neutron source.
Download or read book TMX U Tandem Mirror Experiment Upgrade Tandem mirror Thermal barrier Experiments written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal-barrier experiments have been carried out in the Tandem Mirror Experiment-Upgrade (TMX-U). Measurements of nonambipolar and ambipolar radial transport show that these transport processes, as well as end losses, can be controlled at modest densities and durations. Central-cell heating methods using ion-cyclotron heating (ICH) and neutral-beam injection have been demonstrated. Potential mesurements with recently developed methods indicate that deep thermal barriers can be established.
Download or read book Organization and Performance of the Neutral Beam System for the Tandem Mirror Experiment Upgrade TMX U written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Tandem Mirror Experiment-Upgrade (TMX-U) at Lawrence Livermore National Laboratory (LLNL) uses 24 neutral-beam injectors to heat and fuel the experimental plasmas. This system is unique because TMX-U operates four times more injectors than any other fusion experiment. These injectors deliver an average of 50 A (accel) at 17 keV for 75 ms. Source conditioning time has been reduced to approximately four days for the entire system after extended machine air cycles. TMX-U is also unique because it has 35 usable injector assemblies for the 24 power systems. This quantity of injectors makes possible the development of new hardware and injector modifications, and the reconditioning of damaged sources without affecting machine operation. Efficient operation of a system of this size requires coordinated interaction between the injector service groups and the physics organization. We describe the current state of TMX-U performance and the aspects of group interaction essential to a project of this size.
Download or read book Electron Cyclotron Resonance Heating ECRH in the TMX Upgrade Tandem mirror Experiment written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book INIS Atomindeks written by and published by . This book was released on 1987 with total page 1260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Changes and Developments in Electron Cyclotron Resonant Heating ECRH on the Tandem Mirror Experiment Upgrade TMX U written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Fundamental Mode Rectangular Waveguide System for Electron cyclotron Resonant Heating ECRH for Tandem Mirror Experiment upgrade TMX U written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a brief history of TMX-U's electron cyclotron resonant heating (ECRH) progress. We emphasize the 2-year performance of the system, which is composed of four 200-kW pulsed gyrotrons operated at 28 GHz. This system uses WR42 waveguide inside the vacuum vessel, and includes barrier windows, twists, elbows, and antennas, as well as custom-formed waveguides. Outside the TMX-U vessel are directional couplers, detectors, elbows, and waveguide bends in WR42 rectangular waveguide. An arc detector, mode filter, eight-arm mode converter, and water load in the 2.5-in. circular waveguide are attached directly to the gyrotron. Other specific areas discussed include the operational performance of the TMX-U pulsed gyrotrons, windows and component arcing, alignment, mode generation, and extreme temperature variations. Solutions for a number of these problems are described.
Download or read book Physics Briefs written by and published by . This book was released on 1990 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt:
