How does ITER plan to produce its plasma current?

[rabbit44]

I've been looking on the internet and can't find the answer to this question. I'd like to know if it is generating current purely via the traditional inductive method, or if they plan to use any non-inductive method. I suspect the former but I need to know for certain.

And could anyone confirm that JET doesn't use any non-inductive methods?

Thanks for any help.

 

[theCandyman]

According to the ITER website:

Within the tokamak, the changing magnetic fields that are used to control the plasma produce a heating effect. The magnetic fields create a high-intensity electrical current through induction, and as this current travels through the plasma, electrons and ions become energized and collide.

And from there the other heating methods are introduced. What other ways of generating a current in a plasm are there?

 

[Astronuc]

Besides Ohmically (by virtue of resistance to induced current) heating the plasma, magentic compression may be used. Beyond that are neutral beam injection, which also can be use to fuel the reactor, and microwave heating (in which the microwaves are coupled to the plasma by matching a characteristic frequency, e.g. electron cyclotron radiation heating).

Ohmic heating, neutral beam injection and high-frequency waves will work together in the ITER tokamak to bring the plasma to a temperature where fusion can occur. Ultimately, researchers hope to achieve a "burning plasma" - one in which the energy of the Helium nuclei produced by the fusion reaction is enough to maintain the temperature of the plasma. The external heating methods can then be strongly reduced or switched off altogether. A burning plasma in which at least 50 percent of the energy to drive the fusion reaction is generated internally is an essential step to reaching the goal of fusion power generation.

http://www.iter.org/SCI/Pages/Heating.aspx



Perhaps of interest: http://epsppd.epfl.ch/London/pdf/P4_171.pdf

 

[theCandyman]

I didn't realize the other heating methods generated a current, but now that I think about it they are forcing charged particles along as well.

 

[Astronuc]

I was thinking more in terms of heating.

The current is generated inductively, based on the principles used in a transformer. The current heats the plasma and generates a confining azimuthal magnetic field.

 

[rabbit44]

Thanks very much for the replies guys. The other current method I was thinking of was the 'bootstrap' method. I had only seen talk of it being discovered, but further research implies that they will be experimenting with it in ITER.

Another question which is more fundamental: a Tokamak generates current via induction like in a transformer, right? As the current through a primary coil increases, stops, decreases through zero and maxes out the other way, we get an induced current generated in the plasma. But at some point during that process the induced current is zero. As the current is required to produce a confinement field, what happens? Is confinement lost between every pulse?