Measurement of electron density profile by microwave reflectometry on tokamaks

Abstract

A new method for measuring the electron density spatial profile has been successfully tested on the tokamak of Fontenay aux Roses (TFR). This method is based on the total reflection experienced by a wave of frequency F on the layer where F=Fpe(r). The experimental results show that the maximum electron density in the discharge is also easily measured and that accurate determination of a density profile can be obtained with a time resolution of 5 ms. This diagnostic is well adapted to all fusion devices where access to the total plasma cross section is limited, particularly for large tokamaks.

2D full-wave simulation of ordinary mode reflectometry

“…During the last few years, reflectometry has proved to be a very useful diagnostic on several large toroidal plasma experiments (Simonet, 1985, Hubbard, 1987, Millot, 1990, Doyle, 1990. Not only have density profiles been measured, but large amounts of qualitative information have been gathered about fluctuations on these machines (TFR Group, 1985, Doyle, 1990, Hanson, 1990.…”

Microwave reflectometry for magnetically confined plasmas

“…Since the first application of this method to laboratory plasmas 5,6 and the proposal of employing FM-CW radar techniques in combination with swept millimeter-wave oscillators, 7,8 microwave reflectometry has matured very quickly, and nowadays finds extensive use in tokamak research. 9,67 Its modest requirement for plasma accessibility and the possibility of conveying microwaves to a remote location make this an ideal method for a fusion reactor. [68][69][70][71][72][73][74][75][76] Another area where microwave reflectometry can play a crucial role is in the detection of short-scale turbulence, which appears to be the cause of anomalous transport in high temperature plasmas.…”

Разработка Комплекса Двухполяризационной Рефлектометрии Торсатрона Ураган-2м

“…Первые эксперименталь-ные результаты, использующие эту методику, опубли-кованы в [5]. В настоящее время рефлектометрия с использованием O-волны наряду с томпсоновским рас-сеянием и интерферометрией широко применяется для измерения профиля плотности плазмы в термоядерных ловушках [6][7][8][9] и др. Следует отметить, однако, что потенциал рефлектометрии для традиционного изме-рения профилей плотности далеко не исчерпан.…”

“…Как следует из (2), для определения профиля плот-ности необходимо знать d (ω)/dω. В действующих комплексах рефлектометрии для измерения d (ω)/dω используется быстрое свипирование частоты генерато-ра [6,10]. При известных dω/dt и сигнале с фазового…”