Recent content by Logarythmic

Yeah Faraday's law holds, so maybe \frac{\eta}{\mu_0} \nabla^2 \vec{B} - (\nabla \cdot \vec{v})\vec{B} - \frac{\partial \vec{B}}{\partial t} = 0 is a correct answer? But what about the behaviour of the field lines? Could one say that for high resistivity the current is zero and the magnetic...

Homework Statement Two of the MHD equations can be formulated as \vec{E} + \vec{v} \times \vec{B} = \eta \vec{J} \nabla \times \vec{B} = \mu_0 \vec{J} where [itex]\eta[/tex] is the resistivity of the plasma. a.) Derive an equation for the magnetic field at very high resistivity and...

Sometimes I feel so smart that I don't know what to do with myself. ;) Thanks!

I tried with \vec{B} = B_0 \sin{[i(kx-\omega t)]} so \nabla \times \vec{E} = i \omega B_0 \cos{[i(kx-\omega t)]} But that doesn't really help me.

Homework Statement Show that all longitudinal waves must be electrostatic by using Faraday's law. Homework Equations Faraday's law: \frac{\partial \vec{B}}{\partial t} = - \nabla \times \vec{E} The Attempt at a Solution Where should I start??

Homework Statement I'm trying to solve a problem related to the solar wind pressure at Jupiter but I'm stuck at calculating the density. It is stated that the solar wind has a density of 5 [itex]cm^{-3}[/tex] and a speed of 400 km/s at the orbit of the Earth, and that it should be assumed...

Got it, so w(x) = \int_{-u_0}^{u_0} i2 \pi v e^{i2 \pi vx} dv = \frac{1}{\pi x^2} \left[ 2 \pi u_0 x \cos{(2 \pi u_0 x)} - \sin{(2 \pi u_0 x)} \right]

\int f(v) e^{iavx} dv = \int f(v) \left( \cos{avx} + i \sin{avx} \right) dv = = \int f(v) \cos{avx} dv + i \int f(v) \sin{avx} dv Maybe?

How do I solve an integral of the type \int f(v) e^{iavx} dv ? Can I just treat i as any other constant?

I'm using that paper, my problem is that I'm not really sure about the definition of counts.

How can I find the number of Rayleighs per count if I know the column emission rate, radiance, irradiance, #photons per pixel and #photoelectrons per pixel? I'm totally lost in this one, please help!

Hey everyone! I am currently on a project building a small CanSat. This is a small satellite of the size of a coke can which will be launched together with a balloon and then descend from an altitude of 35 000 m. My problem now is to work out the heat conduction to see if our insulation is...

I did it with the Lorentz Force on the guiding center and got the equation given by Astronuc but with a plus sign. I guess that the sign is dependent on the charge.

I thought about that too, but it's stated in the problem that the motion is periodic with period \Omega. Anyway, my question still remains.

I have two parametric equations for the speed of a particle in a plane: \dot{x}(t) = A \left( 1 - cos{\Omega t} \right) \dot{y}(t) = A sin{\Omega t} The period is equal to \Omega. How do I find the wavelength of the motion? The wavelength is just \lambda = \Omega v , where v =...