One of my few criticism of Freidberg's papers is the cost function that he uses. I think it's a very good paper, and I know that he chose to use simple models clarity. But there are costs and economic risks associated with large scale projects, like ITER, that his cost function does not account...
I wasn't around at the snowmass conferences when the US decided to rejoin ITER. But I've talked with many senior scientists who were there, and from what I understand there was a lot of concern back then that Q=10 was too big of a jump. As I understand it at the time the debate was to rejoin...
ITER is not designed to maximize research output. ITER was designed to demonstrate Q=10. ITER has paper thin engineering margins. One unmitigated disruption at full power has the potential to damage the device beyond repair. As a result every experiment on ITER will have to be meticulously...
You should be very skeptical of anyone making this claim. Most of the people making this claim are basing the claim off of very crude back of the envelope calculations. But we have 50+ years of experience that shows that these back of the envelope calculations simply don't cut it.
ITER proves...
We are not building this experiment. Lockheed is building this experiment. I honestly don't know why Lockheed went with this design. I haven't seen anything that convinces me that Lockheed's design is an improvement over traditional cusps or traditional mirrors. There's no experimental evidences...
Depending on who you ask this isn't an accurate account of history. It is true that tokamaks showed better confinement than mirrors. But the decision to abandon the mirror program was mostly due to massive budget cuts to the fusion program. We didn't abandon the mirror because it was a failed...
The are a zoo of different confinement regimes in Tokamaks. The "standard" confinement regime is call the L-mode which is a low confinement regime. However, it was observed that with sufficient input power the tokamak plasma will spontaneously transition to a high confinement regime which we...
Impurity transport isn't my area of expertise so please correct me if I'm wrong. My understanding is we normally define a figure of merit based on ratio the helium particle confinement time to the global energy confinement time \tau_{He}^*/ \tau_E and it's generally assumed that \tau_{He}^*/...
The are a few labs that are looking at ways to use a fusion reactor as a neutron generator. If you not interested in producing energy, then it's actually very easy to use fusion to produce high energy neutron. These neutrons have a number of scientific and industrial uses. For instance these...
The first wall is a mechanical structure that is composed of many different components. The plasma facing components are the parts of the first wall that face the plasma.
The easy thing to do is calculate the collision frequency and compare that with the fusion reaction rate. You'll see that the collision frequency is much more rapid than the fusion rate. Qualitatively this tells you that the energy lost due to scattering is the dominate mechanism at play.
There...
In order to use a genetic algorithm you need a model that can be used to judge the fitness of an individual solution. In fusion research there are many situations where our models are not accurate enough.
I do know of a few cases where fusion scientist have used genetic algorithms in their...
Forget the magnetic field for now. Adding a magnetic field is a form of confinement, and this problem that you're trying to understand is why confinement is necessary. To understand this problem you should to consider the case of an unconfined plasma. I very strongly recommend that you ignore...
The problem with beam fusion is that on average scattering will knock particles out of a beam before they can fuse.
Scattering is a process that coverts a beam of particles into a thermal distribution of particles. Scattering does nothing to a uniform thermal distribution of particles. If you...