H-1 Heliac: Parameters 3 period heliac: 1992 Major radius1m Minor radius0.1-0.2m Vacuum chamber33m 2 Aspect ratio5+ Magnetic Field1 Tesla (0.2 DC) Heating.

H-1 Heliac: Parameters3 period heliac: 1992Major radius 1mMinor radius 0.1-0.2mVacuum chamber 33m2

Aspect ratio 5+Magnetic Field 1 Tesla (0.2 DC)Heating Power 0.2(0.4)MW GHz ECH

0.3MW 6-25MHz ICH

Parameters: achieved / expected n 3e18/1e19

T ~100eV(Ti)/0.5-1keV(Te)

0.1/0.5%

H-1 Heliac: Parameters3 period heliac: 1992Major radius 1mMinor radius 0.1-0.2mVacuum chamber 33m2

Aspect ratio 5+Magnetic Field 1 Tesla (0.2 DC)Heating Power 0.2(0.4)MW GHz ECH

0.3MW 6-25MHz ICH

Parameters: achieved / expected n 3e18/1e19

T ~100eV(Ti)/0.5-1keV(Te)

0.1/0.5%

Complex geometry requires minimum 2D diagnostic

Cross-section of the magnet structure showing a 3x11 channel tomographic diagnostic

Plasma production and heating: resonant and non-resonant RF

0

0.5

1

1.5

2

2.5

3

3.5

0 1000 2000 3000 4000 5000 6000 7000 8000

(E_DENS IN*10 1̂8m -̂3)

Hydrogen

Series3

Series4

Series5

Poly.((E_DENS IN*10 1̂8m -̂3))Poly.(Series3)

Poly.(Series4)

Helicon wave (non resonant) heating Ion cyclotron resonant heating:Hydrogen, andMinority H in He

argon

H:He

H

CH On axis

<ne> 1018m-3

• Non-resonant heating is flexible in B0, works better at low fields.

• Resonant heating is much more successful at high fields.

= Chon axisMagnetic Field (T)

helicon/frame antenna

Update with helium, Tesla

2D electron density tomography

coherent drift mode in argon, 0.08TH density profile evolution (0.5T rf)

Helical axis non-circular need true 2D

Movie Clip (AVI)

Raw chordal data Tomographically inverted data

radi

us

Ion Temperature Camera

Hollow Ti at low B0

0 10 20 30 time (ms)

Inte

nsity

te

mpe

ratu

re

rot

atio

n

Confinement transitions in H-1

6

5

4

3

2

1

00

0 . 5

1r / a

01 0

2 03 0

t ( m s )

I s i ( )m A( a )

M o d u l a t i o ni n v e r s i o n

“Pressure” (Is) profile evolution during transition

transition

PRF (kW)

B0(T)

•many features in common with large machines

•associated with edge shear in Er

•easily reproduced and investigated

Parameter space map, ~ 1.4

ExB and ion bulk rotation velocity in high confinement mode: magnetic structure causes

viscous damping of rotation

-6E+6

-4E+6

-2E+6

0E+0

2E+6

15 20 25

V_pol(cm/s)

(x10)

VExB

r(cm) (cm)

LCFS (cm)

pttpir BVBVPzen

E 1

0 0

Vp, Vt << VExB ~ 1/(neB) dPi/dr

Radial force balance

Mass (ion) flow velocities much smaller than corresponding VExB

Bulk Rotation Impeded