Nonlinear Kinetic Ion Response to Small Scale Magnetic Islands in Tokamak Plasmas: Neoclassical Tearing Mode Threshold Physics.

08:00 EDT 26th October 2018 | BioPortfolio

Summary of "Nonlinear Kinetic Ion Response to Small Scale Magnetic Islands in Tokamak Plasmas: Neoclassical Tearing Mode Threshold Physics."

A new drift-kinetic theory of the ion response to magnetic islands in tokamak plasmas is presented. Small islands are considered, with widths w much smaller than the plasma radius r, but comparable to the trapped ion orbit width ρ_{bi}. An expansion in w/r reduces the system dimensions from five down to four. In the absence of an electrostatic potential, the ions follow stream lines that map out a drift-island structure that is identical to the magnetic island, but shifted by an amount ∼ few ρ_{bi}. The ion distribution function is flattened across these drift islands, not the magnetic island. For small islands, w∼ρ_{bi}, the shifted drift islands result in a pressure gradient being maintained across the magnetic island, explaining previous simulation results [E. Poli et al., Phys. Rev. Lett. 88, 075001 (2002)PRLTAO0031-900710.1103/PhysRevLett.88.075001]. To maintain quasineutrality an electrostatic potential forms, which then supports a pressure gradient in the electrons also. This influence on the electron physics is shown to stabilize small magnetic islands of width a few ion banana widths, providing a new threshold mechanism for neoclassical tearing modes-a key result for the performance of future tokamaks, including ITER.


Journal Details

This article was published in the following journal.

Name: Physical review letters
ISSN: 1079-7114
Pages: 175001


DeepDyve research library

PubMed Articles [22773 Associated PubMed Articles listed on BioPortfolio]

Nonlinear Decay and Plasma Heating by a Toroidal Alfvén Eigenmode.

We demonstrate theoretically that a toroidal Alfvén eigenmode (TAE) can parametrically decay into a geodesic acoustic mode and kinetic TAE in a toroidal plasma. The corresponding threshold condition ...

Enhanced Third-Order Optical Nonlinearity Driven by Surface-Plasmon Field Gradients.

Efficient nonlinear optical frequency mixing in small volumes is key for future on-chip photonic devices. However, the generally low conversion efficiency severely limits miniaturization to nanoscale ...

A new method for the accurate measurement of higher-order frequency response functions of nonlinear structural systems.

Higher-order frequency response functions (FRFs) are important to the analysis and identification of structural nonlinearities. Though much research effort has been devoted recently to their potential...

Integration of fiber Bragg grating temperature sensors in plasma facing components of the WEST tokamak.

Plasma Facing Components (PFC) temperature measurement is mandatory to ensure safe high power and long pulse tokamak operation. IR thermography systems which are widely used in magnetic fusions device...

Role of Kinetic Instability in Runaway-Electron Avalanches and Elevated Critical Electric Fields.

The effects of kinetic whistler wave instabilities on the runaway-electron (RE) avalanche is investigated. With parameters from experiments at the DIII-D National Fusion Facility, we show that RE scat...

Clinical Trials [10329 Associated Clinical Trials listed on BioPortfolio]

Real-Time Assessment Of Breast Cancer Lumpectomy Specimen Margins With Nonlinear Microscopy

This research is studying a new investigative imaging instrument called a nonlinear microscope (NLM). A nonlinear microscope can produce images similar to an ordinary pathologist's microsc...

Kinetic Anesthesia Device Study

Patients experience discomfort from lidocaine injections. Vibrating kinetic anesthesia devices have been shown to reduce pain of injections in dentistry, pediatrics, and dermatology, thoug...

Least Invasive Nonlinear Light Microscopy

Evaluate the ability to image oral mucosa in healthy volunteer by nonlinear microscopy

Non-linear Multimodal Microendoscopy for Lung Cancer Pathology

For this study the investigators are looking to do the following: 1. To characterize human lung lesions by nonlinear microscopy using ex vivo tissues. 2. To establish the first spect...

Influence of Different Physical Education Pedagogical Approaches on the Health and Development of 5-6 Year Old Children

The Skill Acquisition Methods underpinning Pedagogy for LEarning in Physical Education (SAMPLE-PE) project aims to investigate the influence of different pedagogical approaches to teaching...

Medical and Biotech [MESH] Definitions

A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response.

A scale comprising 18 symptom constructs chosen to represent relatively independent dimensions of manifest psychopathology. The initial intended use was to provide more efficient assessment of treatment response in clinical psychopharmacology research; however, the scale was readily adapted to other uses. (From Hersen, M. and Bellack, A.S., Dictionary of Behavioral Assessment Techniques, p. 87)

A subjective psychometric response scale used to measure distinct behavioral or physiological phenomena based on linear numerical gradient or yes/no alternatives.

Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.

Microscopic imaging techniques that utilize nonlinear responses of light-matter interactions which occur with high-intensity illumination, such as from LASERS, and specialized light signal detection instrumentation to produce images without the need for dyes or fluorescent labels.

Quick Search


DeepDyve research library

Relevant Topic

Blood is a specialized bodily fluid that delivers necessary substances to the body's cells (in animals) – such as nutrients and oxygen – and transports waste products away from those same cells.  In vertebrates, it is composed of blo...

Searches Linking to this Article