Download or read book Alpha Particle Diagnostic written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

Download or read book An Alpha Particle Diagnostic Based on Measurements of Lower Hybrid Wave Fluctuations written by K. L. Wong and published by . This book was released on 1989 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Alpha particle Diagnostics written by and published by . This book was released on 1991 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper will focus on the state of development of diagnostics which are expected to provide the information needed for [alpha]- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence [alpha]-particle birth profile, (2) measurement of the escaping [alpha]-particles and (3) measurement of the confined [alpha]-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by [alpha]-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

Download or read book The Status of Alpha particle Diagnostics written by D. W. Johnson and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Status of Alpha particle Diagnostics written by and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a flurry of activity to complete alpha-particle diagnostics so that they can undergo some experimental testing in DT plasmas on JET or TFTR prior to implementation on ITER. Successful measurements of escaping charged fusion products have been made in DD plasmas, and the [alpha]-particle source can be well characterized by neutron profile measurement. These methods can be extrapolated to DT plasmas. Measurement of the confined [alpha]-particles requires a new technique. Collective Thomson scattering, methods involving charge-exchange interactions and nuclear reactions with impurities will be discussed. Some assessment is given of the capabilities of these techniques, bearing in mind the potential for their use in the physics phase of the ITER program.

Download or read book Alpha particle Diagnostics written by Kenneth M. Young and published by . This book was released on 1991 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Alpha Particle Diagnostic Based on Measurements of Lower Hybrid Wave Fluctuations written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is shown that the one-dimensional alpha particle velocity distribution function can be determined from the fluctuation- dissipation theorem based on measurements of lower hybrid wave fluctuations in an equilibrium plasma. This method uses collective Thomson scattering data with large signal-to-noise ratio, but it is applicable only when the alpha particles have an isotropic velocity distribution. 16 refs., 1 fig.

Download or read book A Nuclear Diagnostic for Fast Alpha Particles written by L. R. Grisham and published by . This book was released on 1982 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A New Alpha Particle Diagnostic Using Knock on Ion Tails written by and published by . This book was released on 1994 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: We propose a new method of measuring the fast confined ct-particle distribution in a reacting plasma. The presence of ct-particles in a D-T plasma will create a high energy tail on the deuterium and tritium ion energy distributions. A 3.5 MeV alpha can transfer 3.4 MeV to a tritium ion in a single elastic scattering interaction. Calculations of the size of these knock-on tails in tokamaks such as TFTR, JET, and ITER show that it may be possible to measure these tails and provide information on the fast confined alphas. The knock-on tail ions will produce D-T neutrons with energies up to 20.7 MeV, so that D-T neutron spectroscopy can be used to monitor the alpha population. Neutron spectroscopy looks especially attractive for ITER. A collimated array of threshold neutron activation detectors could be used to deduce the confined alpha density profile. Tests of this diagnostic can also be done on TFTR and JET. Existing high energy neutral particle analyzers may allow observation of the ion tails directly via passive and/or active charge exchange.

Download or read book ITER Alpha Particle Diagnostics Using Knock on Ion Tails written by and published by . This book was released on 1995 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alpha particles will play a critical role in the physics and successful operation of ITER. Achieving fusion ignition requires that the [alpha] particles created by deuterium-tritium (D-T) reactions deposit a large fraction of their energy in the reacting plasma before they are lost. Toroidal field ripple can localize any alpha particle losses and cause first wall damage. We have proposed a new method of measuring the fast confined [alpha]-particle distribution in a reacting plasma. The same elastic collisions that transfer the alpha energy to the D-T plasma ions and allow fusion ignition will also create a high energy tail on the deuterium and tritium ion energy distributions. Some of these energetic tail ions will undergo fusion reactions with the background plasma producing neutrons whose energy is increased significantly above 14 MeV due to the kinetic energy of the reacting ions. Measurement of this high energy tail on the D-T neutron distribution as a function of plasma minor radius would provide information on the alpha density profile with a time response equal to the ion slowing-down time. Although this technique may provide only limited information on the [alpha]-particle energy distribution, experimental studies of fast ions on existing tokamaks have shown that the observed slowing-down is essentially classical. Hence the [alpha]-energy distribution is expected to be classical except in situations where the [alpha]-confinement is poor. The confinement of [alpha]'s can be affected by ripple losses and a number of instabilities. Toroidal field ripple can cause both prompt orbit losses and stochastic ripple diffusion losses. Magnetohydrodynamic activity, including fishbone instabilities, toroidal Alfven eigenmodes, and sawtooth oscillations, may also affect alpha confinement. The diagnostic proposed here, by monitoring the confined alpha population, can provide valuable information on the confinement of fast alphas in a reacting plasma.

Download or read book Alpha Particle Diagnostics Using 140GHz Microwave Scatteringon JET written by A. E. Costley and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Alpha particle Diagnostics with High Energy Neutral Beams written by M. Sasao and published by . This book was released on 1984 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Alpha Particle Diagnostics Using Impurity Pellet Injection written by and published by . This book was released on 1992 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have proposed using impurity injection to measure the energy distribution of the fast confined alpha particles in a reacting plasma. The ablation cloud surrounding the injected pellet is thick enough that an equilibrium fraction F{sub o}{sup {infinity}}(E) of the incident alphas should be neutralized as they pass through the cloud. By observing neutrals created in the large spatial region of the cloud which is expected to be dominated by the helium-like ionization state, e.g., Li ions, we can determine the incident alpha distribution dn{sub He}2+/dE from the measured energy distribution of neutral helium atoms. Initial experiments were performed on TEXT in which we compared pellet penetration with our impurity pellet ablation model, and measured the spatial distribution of various ionization states in carbon pellet clouds. Experiments have recently begun on TFTR with the goal of measuring the alpha particle energy distribution during D-T operation in 1993--94. A series of preliminary experiments are planned to test the diagnostic concept. The first experiments will observe neutrals from beam-injected deuterium ions and the high energy 3He tail produced during ICH minority heating on TFTR interacting with the cloud. We will also monitor by line radiation the charge state distributions in lithium, boron, and carbon clouds.

Download or read book Some considerations concerning fusion alpha particle diagnostics written by U. Schumacher and published by . This book was released on 1983 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AN ALPHA PARTICLE DIAGNOSTIC BASED ON MEASUREMENTS OF LOWER HYBRID WAVE FLUCTUTIONS written by K.L. WONG. and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Diagnositcs of Magnetically Confined Alpha Particles by Pellet Injection written by and published by . This book was released on 1986 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Some considerations concerning fusion alpha particle diagnostics written by U. Schumacher and published by . This book was released on 1983 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: