Author: Hugo Arnichand
Publisher:
ISBN:
Category :
Languages : en
Pages : 138
Book Description
Plasma Turbulence is responsible of the anomalous transport which degrades the performances of the fusion devices. Turbulence is trigger by different instabilities such as the Ion Temperature Gradient Modes (ITG) and the Trapped Electron Modes (TEM). As ITG and TEM are driven by different gradients, they can either both be stable, both coexist or give way to a single dominant mode. The transport and the toroidal velocity induced by ITG and TEM can be noticeably different thus it is important to be able to discriminate experimentally the dominant modes. Different experimental approaches exist to distinguish ITG from TEM but they are complex and not systematically feasible. This thesis shows that frequency fluctuation spectra can provide an additional experimental indication of the dominant mode.These spectra can show different components:-Broadband spectra (delta-f around hundreds of kHz) which are generally attributed to turbulence.-Coherent modes (delta-f around 1 kHz) which oscillate at a very well-defined frequency.-Quasi-Coherent (QC) modes (delta-f around tens of kHz) which oscillate at a rather well defined frequency but are reminiscent of the broadband fluctuations.Reflectometry measurements and gyrokinetic simulations combined with a synthetic reflectometer diagnostics show that TEM can induce QC modes in the core region of Ohmic plasmas. The QC signature of TEM is due to their narrow frequency spectrum. The QC modes observed in the plasma core were renamed QC-TEM due to their TEM origins. Then, the first applications of these results are made in Ohmic and ECRH plasmas to investigate the role of TEM, and transitions are reported between QC-TEM and MHD modes.
Identification of Trapped Electron Modes in Frequency Fluctuation Spectra of Fusion Plasmas
Author: Hugo Arnichand
Publisher:
ISBN:
Category :
Languages : en
Pages : 138
Book Description
Plasma Turbulence is responsible of the anomalous transport which degrades the performances of the fusion devices. Turbulence is trigger by different instabilities such as the Ion Temperature Gradient Modes (ITG) and the Trapped Electron Modes (TEM). As ITG and TEM are driven by different gradients, they can either both be stable, both coexist or give way to a single dominant mode. The transport and the toroidal velocity induced by ITG and TEM can be noticeably different thus it is important to be able to discriminate experimentally the dominant modes. Different experimental approaches exist to distinguish ITG from TEM but they are complex and not systematically feasible. This thesis shows that frequency fluctuation spectra can provide an additional experimental indication of the dominant mode.These spectra can show different components:-Broadband spectra (delta-f around hundreds of kHz) which are generally attributed to turbulence.-Coherent modes (delta-f around 1 kHz) which oscillate at a very well-defined frequency.-Quasi-Coherent (QC) modes (delta-f around tens of kHz) which oscillate at a rather well defined frequency but are reminiscent of the broadband fluctuations.Reflectometry measurements and gyrokinetic simulations combined with a synthetic reflectometer diagnostics show that TEM can induce QC modes in the core region of Ohmic plasmas. The QC signature of TEM is due to their narrow frequency spectrum. The QC modes observed in the plasma core were renamed QC-TEM due to their TEM origins. Then, the first applications of these results are made in Ohmic and ECRH plasmas to investigate the role of TEM, and transitions are reported between QC-TEM and MHD modes.
Publisher:
ISBN:
Category :
Languages : en
Pages : 138
Book Description
Plasma Turbulence is responsible of the anomalous transport which degrades the performances of the fusion devices. Turbulence is trigger by different instabilities such as the Ion Temperature Gradient Modes (ITG) and the Trapped Electron Modes (TEM). As ITG and TEM are driven by different gradients, they can either both be stable, both coexist or give way to a single dominant mode. The transport and the toroidal velocity induced by ITG and TEM can be noticeably different thus it is important to be able to discriminate experimentally the dominant modes. Different experimental approaches exist to distinguish ITG from TEM but they are complex and not systematically feasible. This thesis shows that frequency fluctuation spectra can provide an additional experimental indication of the dominant mode.These spectra can show different components:-Broadband spectra (delta-f around hundreds of kHz) which are generally attributed to turbulence.-Coherent modes (delta-f around 1 kHz) which oscillate at a very well-defined frequency.-Quasi-Coherent (QC) modes (delta-f around tens of kHz) which oscillate at a rather well defined frequency but are reminiscent of the broadband fluctuations.Reflectometry measurements and gyrokinetic simulations combined with a synthetic reflectometer diagnostics show that TEM can induce QC modes in the core region of Ohmic plasmas. The QC signature of TEM is due to their narrow frequency spectrum. The QC modes observed in the plasma core were renamed QC-TEM due to their TEM origins. Then, the first applications of these results are made in Ohmic and ECRH plasmas to investigate the role of TEM, and transitions are reported between QC-TEM and MHD modes.
Discriminating the Trapped Electron Modes Contribution in Density Fluctuation Spectra
Author: H. Arnichand
Publisher:
ISBN:
Category : Plasma confinement
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category : Plasma confinement
Languages : en
Pages :
Book Description
The Dissipative Trapped Electron Instability in the Linear Multi-mirror Device
Author: David P. Grubb
Publisher:
ISBN:
Category : Plasma instabilities
Languages : en
Pages : 522
Book Description
Publisher:
ISBN:
Category : Plasma instabilities
Languages : en
Pages : 522
Book Description
Fusion Energy Update
Author:
Publisher:
ISBN:
Category : Controlled fusion
Languages : en
Pages : 122
Book Description
Publisher:
ISBN:
Category : Controlled fusion
Languages : en
Pages : 122
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1038
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1038
Book Description
Energy Research Abstracts
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 438
Book Description
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 438
Book Description
Fusion Part A
Author: Edward Teller
Publisher: Elsevier
ISBN: 0323147801
Category : Technology & Engineering
Languages : en
Pages : 505
Book Description
Fusion, Volume I: Magnetic Confinement, Part A is the first of the two-part volume that covers the complexity and application of controlled magnetic fusion. This book is divided into seven chapters and starts with a brief historical overview and some properties of controlled fusion. The subsequent chapters deal with the principles, thermodynamic stability, and configuration of Tokamak plasma. These topics are followed by discussions of the variations and application of stellarators; the concepts of mirror theory; and the establishment of the experimental basis of the mirror-confinement physics. The last chapter focuses on the principles, configuration, and application of the reversed-field pinch. This book will prove useful to physicists, physics students, and researchers.
Publisher: Elsevier
ISBN: 0323147801
Category : Technology & Engineering
Languages : en
Pages : 505
Book Description
Fusion, Volume I: Magnetic Confinement, Part A is the first of the two-part volume that covers the complexity and application of controlled magnetic fusion. This book is divided into seven chapters and starts with a brief historical overview and some properties of controlled fusion. The subsequent chapters deal with the principles, thermodynamic stability, and configuration of Tokamak plasma. These topics are followed by discussions of the variations and application of stellarators; the concepts of mirror theory; and the establishment of the experimental basis of the mirror-confinement physics. The last chapter focuses on the principles, configuration, and application of the reversed-field pinch. This book will prove useful to physicists, physics students, and researchers.
Plasma Physics and Controlled Nuclear Fusion Research
Author:
Publisher:
ISBN:
Category : Controlled fusion
Languages : en
Pages : 716
Book Description
Publisher:
ISBN:
Category : Controlled fusion
Languages : en
Pages : 716
Book Description
Nuclear Science Abstracts
Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 1058
Book Description
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 1058
Book Description
Plasma Physics and Controlled Nuclear Fusion Research, 1971
Author:
Publisher:
ISBN:
Category : Controlled fusion
Languages : en
Pages : 714
Book Description
Publisher:
ISBN:
Category : Controlled fusion
Languages : en
Pages : 714
Book Description