Progress of Magnetic Reconnection experiment in Linear Magnetized Plasma Device

Xie, JinLin & LMPD groupCAS KEY LABORATORY OF BASIC PLASMA PHYSICS

UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINASuzhou, September 24, 2007

Outline• Introduction

– What & Why & How– LMPD in USTC

• What we have done by now– Background plasma– Topology of the magnetic field for MR– Diagnostics / Data Acquisition System / …

• Preliminary result• Future plan

Introduction: Linear Magnetized Plasma Device in USTC

DC, RF & Helicon discharge source；

Bmax: 1000GuassTe:1~10evTi:0.03~0.5evDenisty:108~1013cm-3

Experimental chamber

LIFquad-probe

emissive probelangmuir probe

Nagoya antenna

13.56MHz,2KWMatch network

Radius

Plasma source: Helicon discharge

RF Power

Plas

ma

Den

sity

Typical ParametersTypical ParametersLCD

UCLA Pre-update LMPD LMPD

Machine typical Length[cm] 30 10 10

Plasma Denisty[m-3] 1018 1014 ~1016 1014 ~1019

Electron temperature Te[ev] 10 ~4 1~10

Ion temperature Ti[ev] 2 0.03 0.03~0.5

B for Magnetic Reconnection[T]

0.002 0.01 0.01

Ion mass Mi/Mp 40 40 1~40

Ion sound gyro-radius Rci[cm] 60 13 2~18

Ion skin depth [cm] c/wpi 60 4500 7 ~ 14300

Electron skin depth [cm] c/wpe 0.5 17 0.2 ~ 53

Electron free path [cm] 100 ~40 >100 ~ 3

Resistive time [ms] 1.5 0.2 ~ 0.1

Alfven time[us] 25 <1 0.1 ~ 10

Lundquist number ~60 300 10 ~ 1000

Background plasma for MR experiment

coil Vertical window

Pump

Hor. Window Experimental chamber

Plasma Source

Simulation result via OPERA

Magnetic field for reconnection

7 s 5 s

2500A

time

Curr

ent

Copper plate and Pulse current source

Diagnostics for MR • Characteristic for MR experiment in lab plasma

– High spatial resolution: small size Vs large enough S/N– Wide signal bandwidth: Low freq. ~ MHz or microwave High Spatio-temporal resolution

• What we have now：– 3D B dot probe B0 , B1 Current sheet, E…– Retarding grid energy analyzer EVDF & IVDF & flux– Electrostatic probes: Langmuir probe, emissive probe, Mach

probe… Ne, Te, Vf, Vp, Iion, Ie, Ion flux… – Laser induced fluorescence(LIF) IVDF & ion flux – Microwave antenna and related instrument EM radiation

– DAQ system: 12 channels x 5M; 128 x 2M; 2 x 60M

Vacuum chamber

precision platform for 2D scanning probe

Ion Saturation Current Electron Temperature

1 2 3 4 5 6 7 8 91

2

3

4

5

6

7

8

9

10

11

1.4

1.6

1.8

2

2.2

2.4

2.6

2.8

3

Reconstruction of the magnetic field linein order to verify MR process

x

Vacuum evolution

Research plan

• Verification of MR process in LMPD

• Heating and acceleration of electron & ion

• Electrostatic & electromagnetic turbulence

• ……….

Thank you!