Observations of Alfven Waves in a Tokamak Plasma PDF Download

Author: Anthony Bruce Murphy
Publisher:
ISBN:
Category : Fusion plasma
Languages : en
Pages : 542

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Author: Louis Robert Giannone
Publisher:
ISBN:
Category : High temperature plasmas
Languages : en
Pages : 442

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Author: Rodney Cross
Publisher: CRC Press
ISBN:
Category : Art
Languages : en
Pages : 244

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This valuable introduction to the physics of Alfven waves in laboratory and space plasmas is accessible to anyone with a elementary knowledge of plasma physics. The book will give graduate students all the background information necessary to understand the research literature. Much of the material is recent and may contain some surprises even for experts.

Author: Sergei Sharapov
Publisher: CRC Press
ISBN: 1351002813
Category : Science
Languages : en
Pages : 156

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Book Description
The study of energetic particles in magnetic fusion plasmas is key to the development of next-generation "burning" plasma fusion experiments, such as the International Thermonuclear Experimental Reactor (ITER) and the Demonstration Power Station (DEMO). This book provides a comprehensive introduction and analysis of the experimental data on how fast ions behave in fusion-grade plasmas, featuring the latest ground-breaking results from world-leading machines such as the Joint European Torus (JET) and the Mega Ampere Spherical Tokamak (MAST). It also details Alfvenic instabilities, driven by energetic ions, which can cause enhanced transport of energetic ions. MHD spectroscopy of plasma via observed Alfvenic waves called "Alfvén spectroscopy" is introduced and several applications are presented. This book will be of interest to graduate students, researchers, and academics studying fusion plasma physics. Features: Provides a comprehensive overview of the field in one cohesive text, with the main physics phenomena explained qualitatively first. Authored by an authority in the field, who draws on his extensive experience of working with energetic particles in tokamak plasmas. Is suitable for extrapolating energetic particle phenomena in fusion to other plasma types, such as solar and space plasmas.

Author: Henry James Churston Oliver
Publisher:
ISBN:
Category :
Languages : en
Pages : 338

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Alfvén waves are electromagnetic waves that occur in magnetised plasmas. Alfvén waves are routinely observed in tokamaks — toroidal devices that confine plasma using magnets. Energetic ions that are used to heat the plasma within tokamaks can drive the Alfvén waves unstable. Additionally, alpha particles produced in fusion reactions may destabilise the wave. Alfvén waves with sufficiently high amplitudes can eject energetic particles from the plasma, damaging the reactor and decreasing fusion efficiency. When these waves are not strong enough to eject particles from the plasma, their benign behaviour can be used to diagnose the plasma. This technique is known as magnetohydrodynamic (MHD) spectroscopy. In this thesis, we outline three new techniques of MHD spectroscopy that we have developed. The first new method of MHD spectroscopy was developed in plasmas composed of hydrogen and deuterium in the Mega Ampere Spherical Tokamak (MAST). Compressional Alfvén eigenmodes (CAEs) and global Alfvén eigenmodes (GAEs) were suppressed in plasmas with high hydrogen concentrations. At the highest hydrogen concentrations investigated, high frequency ion-ion hybrid waves appeared. We used a 1D model of the refractive index and wave-particle resonances to explain these observations and estimate the relative ion concentration at which the spectrum of excited waves changed. These estimates agreed with experimental observations, suggesting the spectrum of excited waves can be used to diagnose the relative ion concentrations for plasmas with two ion species. The second new form of MHD spectroscopy was developed using observations of axisymmetric modes in experiments on the Joint European Torus (JET). Axisymmetric modes do not change in the toroidal direction and are driven unstable by energy gradients in the fast particle distribution function. Therefore, we can use observations of the axisymmetric mode to infer information about the gradient of the fast particle energy distribution function. We explained how these axisymmetric modes can exist without heavy damping. We also examined how the elongation of the plasma column modifies the mode using numerical and analytical tools. The final MHD spectroscopic technique was developed for JET plasmas injected with pellets of frozen deuterium, which are used to refuel the plasma core. We demonstrated how key pellet parameters can be inferred from dramatic changes to the Alfvén eigenfrequencies that we observed in JET. MHD spectroscopy of pellet injected plasmas was enabled by generalising two 3D MHD codes to incorporate 3D density profiles. 3D density profiles were generated using a model for the expansion of the pellet wake along a magnetic field line derived from the fluid equations. From the change in mode frequency, we estimate the density of the pellet wake and the time-scale for poloidal homogenisation of the wake. Before presenting these studies, we introduce the basics of fusion, tokamaks, and the models used to describe tokamak plasmas. We then discuss the MHD waves that we will use for MHD spectroscopy of tokamak plasmas, and how these waves are excited by fast particles. The three new methods of MHD spectroscopy are then discussed

Author: Sergei Sharapov
Publisher: CRC Press
ISBN: 9781138545540
Category :
Languages : en
Pages : 152

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Book Description
The study of energetic particles in magnetic fusion plasmas is key to the development of the next generation of "burning" plasma fusion experiments, such as the International Thermonuclear Experimental Reactor (ITER) and the Demonstration Power Station (DEMO). This book provides a comprehensive introduction and analysis of the latest experimental data on how fast ions behave in fusion grade plasmas, featuring the latest ground-breaking results from world leading machines such as the Joint European Torus (JET) and the Mega Ampere Spherical Tokamak (MAST). It also details Alfvenic instabilities, driven by energetic ions, which could cause the stochastic transport of energetic ions. MHD spectroscopy of plasma via observed Alfvenic waves and called "Alfvén spectroscopy" is introduced and several applications are presented. This book will be of interest to graduate students, researchers, and academics studying fusion plasma physics. Key Features: Provides a comprehensive overview of the field in one cohesive text, with main physics phenomena explained qualitatively first Authored by an authority in the field, who draws on his extensive experience of working with energetic particles in fusion plasmas Is suitable for extrapolating energetic particle phenomena in fusion to other types of plasmas, such as solar and space plasmas

Author: Mark John Ballico
Publisher:
ISBN:
Category : High temperature plasmas
Languages : en
Pages : 210

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Author:
Publisher:
ISBN:
Category : Controlled fusion
Languages : en
Pages : 170

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Author: Andreas Keiling
Publisher: John Wiley & Sons
ISBN: 1394195966
Category : Science
Languages : en
Pages : 325

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Book Description
Alfvén Waves Across Heliophysics Progress, Challenges, and Opportunities Alfvén waves are fundamental to the dynamics of space plasmas. Recent advances in our knowledge about Alfvén waves have come from several directions, including new space missions to unexplored heliospheric regions, sophisticated rocket campaigns in the auroral zone, enlarged magnetometer arrays and radar networks, and significant advances in computer modeling. Alfvén Waves Across Heliophysics: Progress, Challenges, and Opportunities is an interdisciplinary collaboration from different space science communities to review recent and current Alfvén wave research. Volume highlights include: Alfvén waves in the solar atmosphere Alfvén waves at the giant planets Alfvén waves at Mars Alfvén waves in moon-magnetosphere systems Alfvén waves in geospace Alfvén waves in the laboratory The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Coupling to shear Alfven wave resonances has been suggested as a promising heating scheme for tokamaks. This technique is being experimentally investigated in Tokapole II. Resonances in the poloidal magnetic wave field have been observed during the RF pulse with resonant peaks on both sides of the separatrix. The location and mode structure of these peaks are consistent with theoretical calculations for the noncircular tokamak plasma indicating the strong possibility that shear Alfven wave resonances are being observed in a tokamak geometry. At present, only basic wave excitation and propagation studies are being performed, with heating studies to follow later.