Download or read book On the Toroidal Plasma Rotations Induced by Lower Hybrid Waves written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A theoretical model is developed to explain the plasma rotations induced by lower hybrid waves in Alcator C-Mod. In this model, torodial rotations are driven by the Lorentz force on the bulk electron flow across flux surfaces, which is a response of the plasma to the resonant-electron flow across flux surfaces induced by the lower hybrid waves. The flow across flux surfaces of the resonant electrons and the bulk electrons are coupled through the radial electric fi eld initiated by the resonant electrons, and the friction between ions and electrons transfers the toroidal momentum to ions from electrons. An improved quasilinear theory with gyrophase dependent distribution function is developed to calculate the perpendicular resonant-electron flow. Toroidal rotations are determined using a set of fluid equations for bulk electrons and ions, which are solved numerically by a fi nite- difference method. Numerical results agree well with the experimental observations in terms of flow pro file and amplitude. The model explains the strong correlation between torodial flow and internal inductance observed experimentally, and predicts both counter-current and co-current flows, depending on the perpendicular wave vectors of the lower hybrid waves. __________________________________________________
Download or read book Theoretical Study of Ion Toroidal Rotation in the Presence of Lower Hybrid Current Drive in a Tokamak written by Jungpyo Lee and published by . This book was released on 2013 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the effect of the lower hybrid current drive on ion toroidal rotation in a tokamak is investigated theoretically. Lower hybrid frequency waves are utilized to drive non-inductive current for steady state tokamaks and ion toroidal rotation is used to control disruptions and improve confinement. It has been observed in many tokamaks that lower hybrid waves can change the ion toroidal rotation. These measurements indicate that it may be possible to control rotation with lower hybrid waves, but to do it, it is necessary to understand the mechanisms underlying the rotation change. The toroidal angular momentum injected by the lower hybrid waves initiates acceleration in the the counter-current direction. The parallel and perpendicular components of the toroidal angular momentum are transferred from the waves to ions through electrons via two different channels, and the ions obtain the full toroidal angular momentum injected by the lower hybrid waves after several ion collision times. The momentum transferred to the ions is transported out by turbulent radial transport. The radial transport of toroidal angular momentum is evaluated using gyrokinetics corrected to the higher order in poloidal rhostar. The higher order corrections lead to momentum redistribution even in the absence of rotation, which is called intrinsic momentum transport. The intrinsic momentum transport due to diamagnetic effects is an important piece of the radial momentum transport. The change in the steady state rotation due to lower hybrid waves is estimated theoretically by evaluating the momentum source, the momentum pinch and diffusion, and the intrinsic momentum transport. The effect of the current profile on the intrinsic momentum transport, which is modified by the lower hybrid wave, may explain the reversal of the rotation change from counter-current direction to co-current direction observed in low plasma current discharges in Alcator C-Mod.
Download or read book Wave Propagation Near the Lower Hybrid Resonance in Toroidal Plasmas written by K. Ohkubo and published by . This book was released on 1975 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lower Hybrid Wave Propagation in Toroidal Plasmas written by Jack Jerome Schuss and published by . This book was released on 1984 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Driven Rotation Self Generated Flow and Momentum Transport in Tokamak Plasmas written by John Rice and published by Springer Nature. This book was released on 2022-01-13 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive look at the state of the art of externally driven and self-generated rotation as well as momentum transport in tokamak plasmas. In addition to recent developments, the book includes a review of rotation measurement techniques, measurements of directly and indirectly driven rotation, momentum sinks, self-generated flow, and momentum transport. These results are presented alongside summaries of prevailing theory and are compared to predictions, bringing together both experimental and theoretical perspectives for a broad look at the field. Both researchers and graduate students in the field of plasma physics will find this book to be a useful reference. Although there is an emphasis on tokamaks, a number of the concepts are also relevant to other configurations.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-03 with total page 938 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Current Generation by Unidirectional Lower Hybrid Waves in the ACT 1 Toroidal Device written by K. L. Wong and published by . This book was released on 1980 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non resonant Parametric Decay of Lower hybrid Waves in the ACT 1 Toroidal Device written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-resonant parametric decay of lower-hybrid waves, observed in a number of high-power tokamak rf heating experiments, is positively identified as a decay into ion-cyclotron quasi-modes. The decay-wave spectrum, wavelength and amplitude profile are measured inside a toroidal plasma with pump frequency f0 approx. 3.5 f/sub .pi./ approx. 25 f/sub ci.
Download or read book Fusion Energy Update written by and published by . This book was released on 1986 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy a Continuing Bibliography with Indexes written by and published by . This book was released on 1980 with total page 1100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On Plasma Rotation Induced by Traveling Fast Alfvin Waves written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Absorption of fast Alfven waves by the minority fundamental ion-cyclotron resonance, coupled with finite banana width physics, generates torque distributions and ultimately rotational shear layers in the bulk plasma, even when the toroidal wavenumber k(subscript ''phi'') = n/R of the fast wave vanishes (n=0) and cyclotron absorption introduces no angular momentum nor canonical angular momentum [F.W. Perkins, R.B. White, P.T. Bonoli, and V.S. Chan, Phys. Plasmas 8 (2001) 2181]. The present work extends these results to travelling waves with non-zero n where heating directly introduces angular momentum. Since tokamak fast-wave antennas have approximately one wavelength per toroidal field coil, the toroidal mode number n lies in the range n = 10-20, independent of machine size. A zero-dimensional analysis shows that the rotation rate arising from direct torque is comparable to that of the rotational shear layer and has the same scaling. Nondimensional rotation profiles for n = ( -10, 10) show modest changes from the n = 0 case in the expected direction. For a balanced antenna spectrum, the nondimensional rotational profile (averaged over n = -10, 10) lies quite close to the n = 0 profile.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-03 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1983 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Documentation of Plasma Physics Pt 1 Experimental Plasma Physics and Theoretical Plasma Physics written by and published by . This book was released on 1981 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1977 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
