Author: Roger RamanPublisher:
ISBN:
Category :
Languages : en
Pages : 24
Book Description
Initial Results from Coaxial Helicity Injection Experiments in NSTX.
Author: Roger RamanInitial Results from Coaxial Helicity Injection Experiments in NSTX.
Author: Roger RamanOverview of the Initial NSTX Experimental Results
Author: Masayuki OnoPublisher:
ISBN:
Category : Neutral beams
Languages : en
Pages : 12
Book Description
U.S. Department of Energy Performance and Accountability Report: Fiscal Year 2002
Author: Publisher: DIANE Publishing
ISBN: 1428918310
Category :
Languages : en
Pages : 294
Book Description
Overview of Impurity Control and Wall Conditioning in NSTX.
Author: H. W. KugelPublisher:
ISBN:
Category : National Spherical Torus Experiment (Project).
Languages : en
Pages : 22
Book Description
Design, Installation and Performance of the New Insulator for NSTX CHI Experiments
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Coaxial Helicity Injection (CHI), a non-inductive method to initiate plasma and generate toroidal plasma current, is being investigated in the National Spherical Torus Experiment (NSTX). The center stack and outer vacuum vessel are separated by insulating gaps at the top and bottom of the slim central column so that a high voltage (up to 2 kV) can be applied between them from a pulsed power supply or a capacitor bank to initiate an arc discharge. In the presence of a suitable poloidal magnetic field, the discharge is initiated at the lower gap (the injector gap) and because of the strong toroidal field develops a helical structure resulting in substantial toroidal plasma current being driven. In NSTX, up to 390 kA of toroidal current has been generated for an injected current of 25 kA. The early investigations of CHI however frequently developed arcs across the insulator at the top of the machine (the absorber gap), which terminated the desired discharge. This arcing greatly restricted the operational space available for CHI studies. During 2002, the absorber region was modified to suppress these arcs. The new design includes a new ceramic insulator on the high field side of the absorber region with a much longer tracking distance between conducting elements at the different potentials. Furthermore, two new coils were installed near the absorber to provide the ability to minimize the poloidal field connecting the center stack and outer vacuum vessel. During the subsequent experimental campaign, CHI operation was less prone to arcing in the absorber and those arcs that did occur did not terminate the main discharge.).
Observation of Persistent Edge Current Driven by Coaxial Helicity Injection (CHI).
Author: D. MuellerRecent Physics Results from NSTX.
Author: R. E. BellPublisher:
ISBN:
Category :
Languages : en
Pages : 14
Book Description
The National Spherical Torus Experiment (NSTX) has made considerable progress in advancing the scientific understanding of high performance long-pulse plasmas needed for ITER and future low-aspect-ratio Spherical Torus (ST) devices. Plasma durations up to 1.6s (5 current redistribution times) have been achieved at plasma currents of 0.7 MA with non-inductive current fractions above 65% while achieving {beta}{sub T} and {beta}{sub N} values of 16% and 5.7 (%mT/MA), respectively. Newly available Motional Stark Effect data has allowed systematic study and validation of current drive sources and improved the understanding of ''hybrid''-like scenarios. In MHD research, six mid-plane ex-vessel radial field coils have been utilized to infer and correct intrinsic error fields, provide rotation control, and actively stabilize the n=1 resistive wall mode at ITER-relevant low plasma rotation values. In transport and turbulence, the low aspect ratio and wide range of achievable {beta} in NSTX provide unique data for confinement scaling studies. A new high-k scattering diagnostic is investigating turbulent density fluctuations with wavenumbers extending from ion to electron gyro-scales. In the area of energetic particle research, cyclic neutron rate drops have been associated with the destabilization of multiple large Toroidal Alfven Eigenmodes (TAEs) similar to the ''sea-of-TAE'' modes predicted for ITER. Three wave coupling processes between energetic particle modes and TAEs have also been observed for the first time. In boundary physics, advanced shape control has been utilized to study the role of magnetic balance in H-mode access and ELM stability. Peak divertor heat flux has been reduced by a factor of 5 using an H-mode compatible radiative divertor, and Lithium conditioning has demonstrated particle pumping and improved thermal confinement. Finally, non-solenoidal plasma start-up research is particularly important for the ST, and Coaxial Helicity Injection has now produced 160kA plasma currents on closed magnetic flux surfaces.
Proceedings of the Fifth Carolus Magnus Euro-Summer School on Plasma and Fusion Energy Physics
Author: Energy and Water Development Appropriations for 2008: Dept. of Energy FY 2008 budget justifications: science, nuclear waste disposal, defense nuclear waste disposal
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water DevelopmentPublisher:
ISBN:
Category : Federal aid to energy development
Languages : en
Pages : 1716
Book Description