Recent content by rabbit44

I can't actually find an explanation of this? I think that bigger plasma volumes suffer less energy/particle loss (and therefore have a greater confinement time), but what is the physical reason for this? Thanks

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...

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...

Thanks very much for replying. So does E, the CM energy, include the rest energies of the incident particles? I just realized also that a large part of my confusion was thinking that the mass of the compound particle is the mass equivalent of its ground state energy. But an excited nucleus...

Thanks for replying, but I don't get how E_R is the mass of the resonant state. Because E_R is the kinetic energy in the centre of mass frame at which resonance occurs (I think). So for a reaction a + B --> X --> where X is the compound nucleus, shouldn't conservation of energy give...

(urgent) Can someone help me understand the factors in the Breit-Wigner formula? Hi, I have the BW formula as: \sigma = \frac{\lambda^2 (2J+1)}{\pi (2S_a+1)(2S_b+1)} \frac{\Gamma^2 / 4}{(E-E_R)^2 + \Gamma^2/4} So E_R: this is described as the 'resonance energy'. I'm pretty sure this is the...

Homework Statement This is what the question says exactly: Assume the universe today is flat with both matter and a cosmological constant but no radiation. Compute the horizon of the Universe as a function of \OmegaM and sketch it. (You will need a computer or calculator to do this).Homework...

Hi, quick question: I have been told that the weak field regime is when the spin orbit interaction dominates over the Zeeman effect. What exactly does this mean? Does it mean that the energy shift relative to the gross energy due to the S-O interaction is much greater than the energy shift...

Hi, this isn't an actual question, but is a confusion inspired by a question I did (hence me not using the template). I'm having trouble with this example. I'm talking about a solenoid (with core, but doesn't really matter), with n turns per unit length, and a current I_0 t going in. \vec{z} is...

Please help! OK so when we looked at the Zeeman effect, we used the states |n, j, l, m> where these are the quantum numbers associated with H, J^2, L^2 and Jz respectively. We derived the perturbation Hamiltonian as h = (eB/2m)(Lz + 2Sz) Then you can work out the energy shifts...

Homework Statement Estimate the size of the fine structure of the 2p conguration in hydrogen-like sodium (i.e. sodium ions with all but the last electron removed). Why can't we use perturbation theory to calculate the effect of the spin-orbit interaction in hydrogen-like uranium...

Homework Statement I have to find the ratio of the lowest TM cutoff frequency to the lowest TE cutoff frequency. Homework Equations The Attempt at a Solution I have derived the general form of the cutoff frequency (which seems to be the same for both). I get the right answer if I...

Homework Statement A transmission line consists of a cylindrical conductor of radius r at a distance d in air from a conducting plane (r >>d). Derive the capacitance per unit length C and the inductance per unit length L and check that 1/sqrt(LC) = c. Homework Equations The...

Homework Statement Hi, I've attached the question as I don't know how to write equations on here without them looking awful.Homework Equations Laplace -> del^2 V=0The Attempt at a Solution I've done the first bit (expression for Q0). For the next bit I tried to solve laplace's equation to find...

OK having done a tad more research I think I can finally phrase this properly. Thanks to your post, I think I get what happens in the focal/Fraunhofer/Fourier plane. However I still would like to know how to find the intensity distribution in the image plane. e.g. if I have a grating...