ccs method to reproduce tokamak plasma shape c auchy c ondition s urface n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
CCS Method to Reproduce Tokamak Plasma Shape ( C auchy C ondition S urface) PowerPoint Presentation
Download Presentation
CCS Method to Reproduce Tokamak Plasma Shape ( C auchy C ondition S urface)

Loading in 2 Seconds...

play fullscreen
1 / 16

CCS Method to Reproduce Tokamak Plasma Shape ( C auchy C ondition S urface) - PowerPoint PPT Presentation


  • 69 Views
  • Uploaded on

CCS Method to Reproduce Tokamak Plasma Shape ( C auchy C ondition S urface). F. Wang* 1 , K. Nakamura 2 , O. Mitarai 3 , K. Kurihara 4 , Y. Kawamata 4 , M. Sueoka 4 , K. N. Sato 2 , H. Zushi 2 , K. Hanada 2 , M. Sakamoto 2 ,

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'CCS Method to Reproduce Tokamak Plasma Shape ( C auchy C ondition S urface)' - nellis


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
ccs method to reproduce tokamak plasma shape c auchy c ondition s urface

CCS Method to Reproduce Tokamak Plasma Shape(Cauchy Condition Surface)

F. Wang*1, K. Nakamura2, O. Mitarai3, K. Kurihara4, Y. Kawamata4,

M. Sueoka4, K. N. Sato2, H. Zushi2, K. Hanada2, M. Sakamoto2,

H. Idei2, M. Hasegawa2, S. Kawasaki2, H. Nakashima2, A. Higashijima2

Prepared and Presented by Wang Feng in ITC-16

Modified and Presented by Kazuo Nakamura in ASIPP

  • IGSES, Kyushu University
  • (Interdisciplinary Graduate School of Engineering Sciences)
  • 2) RIAM, Kyushu University
  • 3) Kyushu Tokai University
  • 4) Japan Atomic Energy Agency
outline
Outline
  • Conventional Tokamak and Spherical Tokamak
    • CPD
  • Cauchy Condition Surface Method
    • Main Principle of CCS Method
    • Equations of Numerical Calculation
  • Motivation
  • Configuration of CPD
  • Magnetic Sensor Dependence
  • Cauchy-Condition Dependence
  • Plasma Current Profile Dependence
  • Summary and Future Work
  • Application of CCS Method to EAST
1 conventional tokamak and spherical tokamak

a

R

Conventional Tokamak

a

R

Spherical Tokamak

1. Conventional Tokamak and Spherical Tokamak

Spherical Tokamak (ST)

Small Aspect Ratio (A=R/a) < 2

High natural elongation

High natural triangularity

Equilibrium and stability properties are much

different with the conventional tokamaks

slide4

CPD (Compact PWI Experimental Device)

RIAM, Kyushu University

  • Plasma major radius: 0.3 m
  • Plasma minor radius: 0.2 m
  • Toroidal field: 0.3 T @ R = 0.25 m
  • Operation period: 1.00 sec for Bt = 0.3 T
  • Operation cycle: 5 min
  • Plasma current: 150 kA

Main parameters of CPD:

2 cauchy condition surface method
2. Cauchy Condition Surface Method
  • Shape reproduction is important for plasma control in a tokamak, especially for non-circular and triangular plasmas.
  • Cauchy-Condition Surface (CCS) method [1] is a numerical approach to reproduce plasma shape. Its main features are as follows:

1) The CCS method can reproduce plasma shape with high precision corresponding to the number and types of available sensors.

2) The CCS method can identify plasma current with an error of less than 2%.

3) The CCS position and shape are insensitive to reproduction accuracy. This is advantageous in the application to the real-time plasma control.

[1] K. Kurihara, Nuclear Fusion, Vol.33, No.3 (1993) 399-412.

CCS method was proposed by Dr. Kurihara and tested on JT-60U.

main principle of ccs method

CCS

Actual Plasma Surface

Main Principle of CCS Method

B = grad F

Cauchy-Condition Surface

Dirichlet (Φ) ?

Neumann (B) ?

Vacuum field

Magnetic

Measurements

Cauchy-Condition Surface

Dirichlet (Φ)

Neumann (B)

Flux Distribution Outside CCS

Actual Plasma Shape

equations of numerical calculation
Equations of Numerical Calculation

(1)

Dirichlet

Neumann

Vacuum field

Flux Loops CCS && PF Coils

(2)

Magnetic Probes CCS && PF Coils

(3)

CCS CCS && PF Coils

(4)

3 motivation
3. Motivation
  • Motivation
    • As for the spherical tokamak, the aspect ratio is much smaller than normal tokamaks, so the shape reproduction precision of CCS method under a spherical tokamak device is checked.
    • In order to apply it in real-time plasma shape control, magnetic sensor dependence and current profile dependence is also studied.
  • Main Steps of Comparison

1. Various ideal flux surfaces corresponding to different plasma profiles are made by equilibrium code.

2. These plasma shapes are reproduced by using CCS method.

3. The original and reproduced shapes are compared.

4 configuration of cpd
4. Configuration of CPD

R: +0.1 ~ +0.8

Z: -0.7 ~ +0.7

PF Coils: 7

Flux Loops: 45

Mesh Size (RxZ): 140x280

Mesh Precision: 0.005m

Ellipse for CCS

Small radius: 0.03m

Large radius: 0.05m

5 magnetic sensor dependence
5. Magnetic Sensor Dependence

Reproduction with 45 flux loops

Reproduction with 26 magnetic probes

The CCS method can reproduce plasma shape of spherical tokamak solely with the measurements of flux loops.

6 cauchy condition dependence
6. Cauchy-Condition Dependence

CCS (M=6)

CCS (M=8)

CCS (M=10)

In case of much elongated and triangular plasmas in spherical tokamak CPD, good precision can be achieved by changing the degrees of parametric freedom of Cauchy-Condition Surface.

7 plasma current profile dependence 1
7. Plasma Current Profile Dependence (1)

li=1.0

li=0.8

li=0.9

In case of circular plasma shape, normally the shape difference of circular plasma shape is less than 1% compared with major radius R.

7 plasma current profile dependence 2
7. Plasma Current Profile Dependence (2)

Shape Difference

X Point difference

Typical plasma shape reproduction

(Ip = 100kA, IPF1=10kA, βp=0.5, li=0.7, κ=2.1)

difference of x point and plasma shape
Difference of X Point and Plasma Shape

Difference of X Point

Difference of Plasma Shape

The differences between CCS method and ECODE are compared. In case of large elongated and triangular double-null plasma of CPD, normally the X point difference is less than 2%, and shape difference is less than 3% compared with major radius R.

8 summary and future work
8. Summary and Future Work
  • Summary

1. The CCS method can reproduce plasma shape of spherical tokamak in good precision solely with the measurements of flux loops or magnetic sensors.

2. In case of much elongated and triangular plasmas in spherical tokamak, good precision can be achieved by increase in degrees of parametric freedom representing the Cauchy condition.

3. The CCS method can reproduce spherical tokamak plasma shape with good precision in different plasma current profiles (li=0.5 ~ 1.0). In case of large elongated and triangular double-null plasma, normally the X point difference is less than 2%, and shape difference is less than 3%.

  • Future Work

In the real plasma discharge experiment, eddy current effect is important, especially at ramp-up stage of plasma current. The effect of eddy current will be taken into account in Cauchy Condition Surface method in future.

application of ccs method to east
Application of CCS Method to EAST
  • Reproduction of plasma shape
    • Consideration of eddy current in startup
    • Real-time reproduction and display