• 検索結果がありません。

In the experiment, we have verified that the Y AG- TS works well for temperature measurements, but the data quality in density profiles is somewhat poor.

N/A
N/A
Info
ダウンロード
Protected

Academic year: 2021

シェア "In the experiment, we have verified that the Y AG- TS works well for temperature measurements, but the data quality in density profiles is somewhat poor. "

Copied!
1
0
0

読み込み中.... (全文を見る)

今ダウンロードする ( 1 ページ )

全文

(1)

§3. Current Status of the YAG Laser System for LHD Thomson Scattering

Yamada, 1., Narihara, K., Hayashi, H., Yamauchi, K.

The LHD Y AG Thomson Scattering (TS) begun to work in the second cycle LHD experiment, and provide a large number of data on electron temperature and density profiles of LHD plasmas. The basic features have been already reported [1]. An example of measured electron temperature profiles is shown in Fig.1.

The temporal and spatial resolutions are 20 msec and about 20 mm, respectively. The large scatters during the initial ECH discharge are due to low electron densities. For high density NB heated plasmas, reliable temperature data are obtained.

In the experiment, we have verified that the Y AG- TS works well for temperature measurements, but the data quality in density profiles is somewhat poor.

The poor data quality in density measurements may be due to the insufficient pointing stability of the Y AG laser used. In the LHD Y AG-TS, the beam transport length is about 50 m, and then very accurate laser transport system is required. We have made some improvements for

3000 ....-. 2000

;>

'-" 0

~ 1000

0 2500

142

the laser system in order to construct stable and accurate laser control system. We believe that the most effective method to obtain required beam stability is using an active feedback controlled steering mirror system, which has been already developed and now checked carefully. The control system will be equipped and operated in the next experiment.

In addition to the fundamental improvements, a multi beam system will be in operation in the third cycle experiment. The multibeam system has been already successfully applied to the CHS Y AG-TS. In the system, up to seven lasers are used whereas single laser used in the second experiment. Two fundamental operational modes are planed; high repetition rate (200 Hz) or high power (2

J)

mode. The former will be useful when rapid plasma phenomena observed, and more reliable measurements may be possible in the later mode even for low density plasmas.

References

[1] Narihara, K., et aI., Fusion Eng. Design, Vo1.34-35, 67 (1997).

[2] Yamada, I., et ai., Europhys. Conf. Abst., Vol. 19C, Part 111,413(1995).

Fig.1. An example of the time evolution of electron temperature profile measured with the YAG-TS.

1.75

参照

今ダウンロードする ( PDF - 1 ページ - 101.30 KB )

関連したドキュメント

We cannot use LAN in the hall

“Breuil-M´ezard conjecture and modularity lifting for potentially semistable deformations after

(3.) In the statement of the criterion

Then it follows immediately from a suitable version of “Hensel’s Lemma” [cf., e.g., the argument of [4], Lemma 2.1] that S may be obtained, as the notation suggests, as the m A

4 Lengths in the core

Correspondingly, the limiting sequence of metric spaces has a surpris- ingly simple description as a collection of random real trees (given below) in which certain pairs of

The key to the proof lies in using anL2 estimate for the densityρ, and us- ing the smallness of the initial velocity gradient, to obtain uniqueness for the density

The proof of the existence theorem is based on the method of successive approximations, in which an iteration scheme, based on solving a linearized version of the equations, is

A one-dimensional quantum Euler-Poisson system for semicon- ductors for the electron density and the electrostatic potential in bounded intervals is considered

In all cited papers, the existence of (strong) steady-state solutions to the quan- tum hydrodynamic equations is shown for sufficiently small current densities j 0 >.. In fact,

and universality in the matrix model

[Mag3] , Painlev´ e-type differential equations for the recurrence coefficients of semi- classical orthogonal polynomials, J. Zaslavsky , Asymptotic expansions of ratios of

(1)ON THE DENSITY OF HAPPY NUMBERS J

After performing a computer search we find that the density of happy numbers in the interval [10 403 , 10 404 − 1] is at least .185773; thus, there exists a 404-strict

The algorithm appears to run in average time that is softly quadratic and we prove that this is the case for almost all of the steps

But in fact we can very quickly bound the axial elbows by the simple center-line method and so, in the vanilla algorithm, we will work only with upper bounds on the axial elbows..