Current profile control by alternating current magnetic helicity injection

2004 ◽  
Vol 11 (5) ◽  
pp. 2014-2025 ◽  
Author(s):  
F. Ebrahimi ◽  
S. C. Prager
Keyword(s):  
Alternating Current ◽  
Magnetic Helicity ◽  
Current Profile ◽  
Helicity Injection ◽  
Profile Control

scholarly journals Hemispheric injection of magnetic helicity by surface flux transport

2019 ◽  
Vol 631 ◽  
pp. A138 ◽  
Author(s):  
G. Hawkes ◽  
A. R. Yeates
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Solar Rotation ◽  
Surface Flux ◽  
Magnetic Helicity ◽  
Solar Cycles ◽  
Flux Transport ◽  
Transport Models ◽  
Radial Magnetic Field ◽  
Helicity Injection

Aims. We estimate the injection of relative magnetic helicity into the solar atmosphere by surface flux transport over 27 solar cycles (1700–2009). Methods. We determine the radial magnetic field evolution using two separate surface flux transport models: one driven by magnetogram inputs and another by statistical active region insertion guided by the sunspot number record. The injection of relative magnetic helicity is then computed from this radial magnetic field together with the known electric field in the flux transport models. Results. Neglecting flux emergence, solar rotation is the dominant contributor to the helicity injection. At high latitudes, the injection is always negative/positive in the northern/southern hemisphere, while at low latitudes the injection tends to have the opposite sign when integrated over the full solar cycle. The overall helicity injection in a given solar cycle depends on the balance between these two contributions. This net injected helicity correlates well with the end-of-cycle axial dipole moment.

RF current drive with magnetic helicity injection

1985 ◽  
Vol 33 (2) ◽  
pp. 257-264 ◽  
Author(s):  
D. K. Bhadra ◽  
C. Chu
Keyword(s):  
Steady State ◽  
Plasma Density ◽  
Electromagnetic Waves ◽  
Current Drive ◽  
Magnetic Helicity ◽  
Finite Frequency ◽  
Helicity Injection ◽  
Steady State Current ◽  
External Injection ◽  
Frequency Current

External injection of magnetic helicity into a plasma may be possible through the introduction of appropriately polarized electromagnetic waves. A concept of steady-state current-drive is presented, based on the validity of conservation of helicity (appropriately defined for finite frequency processes). It is shown that such external injection of helicity can maintain a steady-state current by compensating the volt-seconds consumed through plasma resistivity. Such a mechanism, if experimentally successful, is particularly interesting at high densities because the efficiency of the process does not depend on plasma density, as opposed to other radio-frequency current-drive techniques.

First-principles-driven model-based current profile control for the DIII-D tokamak via LQI optimal control

2013 ◽  
Vol 55 (10) ◽  
pp. 105007 ◽  
Author(s):  
Mark D Boyer ◽  
Justin Barton ◽  
Eugenio Schuster ◽  
Tim C Luce ◽  
John R Ferron ◽  
...  
Keyword(s):  
Optimal Control ◽  
First Principles ◽  
Current Profile ◽  
Model Based ◽  
Profile Control

Steady state experiments on current profile control and long sustainment of high performance LHCD plasmas on the superconducting tokamak TRIAM-1M

2001 ◽  
Vol 41 (10) ◽  
pp. 1483-1493 ◽  
Author(s):  
H. Zushi ◽  
S. Itoh ◽  
K. Nakamura ◽  
M. Sakamoto ◽  
K. Hanada ◽  
...  
Keyword(s):  
Steady State ◽  
High Performance ◽  
Current Profile ◽  
Profile Control ◽  
Superconducting Tokamak

Transport implications of current drive by magnetic helicity injection

2001 ◽  
Vol 8 (11) ◽  
pp. 4839-4848 ◽  
Author(s):  
Ronald W. Moses ◽  
Richard A. Gerwin ◽  
Kurt F. Schoenberg
Keyword(s):  
Current Drive ◽  
Magnetic Helicity ◽  
Helicity Injection

Current profile control experiments in the LHCD plasma on TRIAM-1M

2002 ◽  
Vol 42 (3) ◽  
pp. 340-343 ◽  
Author(s):  
K Nakamura ◽  
S Itoh ◽  
H Zushi ◽  
M Sakamoto ◽  
K Hanada ◽  
...  
Keyword(s):  
Current Profile ◽  
Profile Control
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