Electron temperature and density measurements by using the Thomson scattering system in the tandem mirror GAMMA 10

Ikezoe

Ohta

et al. 2016

Section: Methodsmentioning

confidence: 99%

Direct Observation of Electron Heating by Electron Landau Damping of Alfvén Ion Cyclotron Waves Using Thomson Scattering System in the Tandem Mirror GAMMA 10/PDX

Ikezoe

Ohta

et al. 2016

“…Thomson scattering (TS) is one of the most useful diagnostic methods for measuring electron temperature and density in plasmas and fusion devices [1][2][3][4][5][6][7][8][9][10]. However, lower electron density areas, such as in GAMMA 10/PDX and spherical region of fusion plasmas, require large numerical aperture collection optics, longer scattering lengths, and high-sensitivity detection systems.…”

Section: Introductionmentioning

confidence: 99%

“…However, lower electron density areas, such as in GAMMA 10/PDX and spherical region of fusion plasmas, require large numerical aperture collection optics, longer scattering lengths, and high-sensitivity detection systems. In GAMMA 10/PDX, we installed an yttrium aluminum garnet (YAG)-TS system featuring large angle collection optics, a long scattering length optical system, and a highsensitivity light detection system [8,9]. The YAG-TS system can measure electron temperatures and densities in seven radial positions in a single laser shot at 10 Hz.…”

Section: Introductionmentioning

confidence: 99%

YAG-Thomson Scattering System in GAMMA 10/PDX Central and End Cells

Mouri

Kohagura

et al. 2019

We developed an yttrium aluminum garnet (YAG)-Thomson scattering (TS) system for radial profile measurements of electron temperature and density in the GAMMA 10/PDX central cell. The optical collection system for TS light was constructed from three spherical mirrors and nine bundled optical fibers. The radial positions were intervals less than 5 cm in the range of ± 20 cm and were measured by moving the fixed fiber bundle position from shot to shot. We constructed a multi-pass TS system with laser amplification, which can increase the signal intensity and time resolution of the TS diagnostic system. In addition, we installed the end-TS system using the central-TS YAG laser in order to measure the electron temperature and density in a divertor simulation experimental module in the GAMMA 10/PDX end cell.

“…Thomson scattering (TS) is the most useful diagnostic available to measure the electron temperature and density in fusion devices [1][2][3][4][5][6][7][8][9][10]. To apply a TS system in lower electron density plasmas, such as GAMMA 10/PDX and the spherical region of fusion plasmas, large numerical aperture collection optics and large scattering lengths are required.…”

Section: Introductionmentioning

confidence: 99%

“…To apply a TS system in lower electron density plasmas, such as GAMMA 10/PDX and the spherical region of fusion plasmas, large numerical aperture collection optics and large scattering lengths are required. In GAMMA 10/PDX, we installed an yttriumaluminum-garnet (YAG)-TS system with large angle collection optics and a large scattering length optical system [8,9]. The YAG-TS system can measure radial electron temperatures and densities at seven fixed positions in a single laser shot at 10 Hz.…”

Section: Introductionmentioning

confidence: 99%

Radial Profile Measurements of Electron Temperature and Density Using the Thomson Scattering System in GAMMA 10/PDX

Kohagura

Chikatsu

et al. 2018

We developed the YAG Thomson scattering (TS) system for electron temperature and density radial profiles in a single laser shot in the tandem mirror GAMMA 10/PDX. The optical collection system for the TS light is constructed using spherical mirrors and nine bundled optical fibers. The measurable radial positions are 5-cm intervals in a region of ± 20 cm due to the fixed position of the bundled optical fibers, which are set on a fixedheight optical platform. We replaced this with a lab jack to make the bundled optical fiber positions movable. Consequently, we can measure the radial profiles of the electron temperature in more detail. Moreover, we added a third spherical light collection mirror at the bottom of the main spherical collection mirror to increase the TS light intensity in the edge plasma region. In this way, we can obtain a slightly larger TS signal intensity than in the case without a third collection mirror. The radial electron temperatures and densities at 15 radial positions in GAMMA 10/PDX are successfully obtained. For the in-situ calibration of the electron density measurements of the TS system, we compare the TS system measurements to the electron line density measured using a microwave interferometer system.