A Dispersion Interferometer Based on a CO2 Laser

Solomakhin, A. L.; Bagryanskii, P.A.; Voskoboinikov, R. V.; Zubarev, P. V.; Kvashnin, A. N.; Lizunov, A. A.; Maksimov, V. V.; Khilchenko, A. D.

doi:10.1007/s10786-005-0116-9

Cited by 9 publications

(7 citation statements)

References 10 publications

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“…In this one we focus on plasma dynamics at the early stage before the NBI switch-on. As a typical example, figure 4 shows the line-averaged plasma density measured at the midplane by a dispersion interferometer (DI) [29] and stray radiation signal measured by a microwave antenna diode. According to the stray radiation signal, after a short ~100-300 µs period of poor microwave absorption, the plasma becomes opaque and stays such until the gyrotron switch-off.…”

Section: Ecr Startup Scenariomentioning

confidence: 99%

Electron cyclotron plasma startup in the GDT experiment

et al. 2016

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The paper reports on a new plasma startup scenario in the Gas Dynamic Trap (GDT) magnetic mirror device. The primary 5 MW neutral beam injection (NBI) plasma heating system fires into a sufficiently dense plasma target ("seed plasma"), which is commonly supplied by an arc plasma generator. In the reported experiments, a different approach to seed plasma generation is explored. One of the channels of the electron cyclotron resonance (ECR) heating system is used to ionize the neutral gas and build up the density of plasma to a level suitable for NBI capture. After a short transition (about 1 ms) the discharge becomes essentially similar to a standard one initiated by the plasma gun. The paper presents the discharge scenario and experimental data on the seed plasma evolution during ECR heating, along with the dependencies on incident microwave power, magnetic configuration and pressure of a neutral gas. The characteristics of consequent high-power NBI discharge are studied and differences to the conventional scenario are discussed. A theoretical model describing the ECR breakdown and the seed plasma accumulation in a large scale mirror trap is developed on the basis of the GDT experiment.

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Section: Ecr Startup Scenariomentioning

confidence: 99%

Electron cyclotron plasma startup in the GDT experiment

et al. 2016

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“…5 The experimental performance of the crystal in the dispersion interferometer based on ZnGeP 2 is not reported in recent publications, 3, 4 but a preliminary report states that this crystal produced 0.02 mW of second-harmonic power with 1 W of input power at a fundamental wavelength of 9.5 μm and 0.008 mW of second-harmonic power with 1 W of input power at a fundamental wavelength of 10.2 μm. 22 The present system, which already produces significantly more peak power than these published results, can be scaled to much higher output powers by using better thermal management. The harmful effect on SHG efficiency in OP-GaAs due to high average power was also observed by Guha and coworkers.…”

Section: Discussionmentioning

confidence: 73%

CO2 laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements

Bamford

Cummings

Panasenko

et al. 2013

Review of Scientific Instruments

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A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 10(17) m(-2) in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.

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“…3 приведена линейная плотность электронов в режимах с инжекцией и без инжекции в КП ГДЛ фокусиро-ванных атомарных пучков. Данные измерения проводились в западном КП (КП-З) с помощью диспер-сионного интерферометра [10], работающего в составе диагностического комплекса ГДЛ. В первом приближении линейной плотности электронов соответствует линейная плотность горячих ионов, по-скольку в области плазмоида количество теплой мишенной плазмы мало.…”

Section: создание амбиполярных барьеров в концевых пробкотронах гдлunclassified

Electronic Structure Investigations of Hydrocarbon Films Obtained Under Controllable Plasma Conditions of T-10 Tokamak

Svechnikov¹,

Stankevich²,

Arkhipov³

et al. 2012

PAST-TF

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В физике открытых ловушек одной из ключевых проблем является проблема продольного удержания плазмы. В разные годы было предложено несколько эффективных способов ограничения продольных потоков частиц и энергии из пробкотронов: ам-биполярные ячейки, гофрированные ловушки и др. В предлагаемой статье описываются результаты экспериментов по созда-нию эффективных амбиполярных барьеров для подавления продольных потерь из установки Газодинамическая ловушка (ГДЛ). Основной целью выполнения данной работы было экспериментальное исследование влияния амбиполярных электрических полей, создаваемых в двух дополнительных концевых пробкотронах («амбиполярных пробках») популяцией горячих анизо-тропных ионов, на продольное удержание плазмы в газодинамической ловушке. Эти исследования продемонстрировали улуч-шение продольного удержания плазмы в ГДЛ при использовании двух амбиполярных барьеров, в результате чего параметр nτ|| в приосевой области был увеличен более чем в 6 раз.Ключевые слова: плазма, открытые магнитные ловушки, амбиполярное удержание. EXPERIMENTAL STUDY OF THE AMBIPOLAR PLASMA CONFINEMENT AT GDT DEVICE A.V. Anikeev, P.A. Bagryansky, A.S. Donin, K.V. Zaytsev, M.S. Korzhavina, A.A. Lizunov, A.N. Lozhkina, V.V. Maksimov, V.V. Prikhodko, E.I. Soldatkina, A.L. Solomakhin Budker Institute of Nuclear Physics SB RAS, Novosibirsk State University, Novosibirsk, RussiaThe key problem of the mirror traps is the longitudinal plasma confinement. Over the years, several ways how to suppress the longitudinal flow of particles and energy from the mirror cell were suggested: ambipolar plugs, multi-mirror traps, etc. This paper presents the results of plasma experiment with two ambipolar end-plugs at GDT devise in the Budker Institute, Novosibirsk. The main objective of the presented research was influence of electric potential created in end-plugs by neutral beam injection on axial plasma confinement at GDT. The experiment demonstrated effective suppression of longitudinal losses and improvement of plasma confinement nτ up to 6 times.

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A Dispersion Interferometer Based on a CO2 Laser

Cited by 9 publications

References 10 publications

Electron cyclotron plasma startup in the GDT experiment

Electron cyclotron plasma startup in the GDT experiment

CO2 laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements

Electronic Structure Investigations of Hydrocarbon Films Obtained Under Controllable Plasma Conditions of T-10 Tokamak

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