# Questions tagged [magnetohydrodynamics]

Magnetohydrodynamics or MHD is a magnetized fluid approximation to the kinetic theory describing a gas composed of charged particles.

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### Velocities in MHD and Plasmas

I have been reading an article about the interaction of a planet within a pulsar wind. However I got confused about some of the velocities and reference frames. There are two reference frames: ...
1 vote
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### Hollow Conical Shell Z-pinch Lithium Penning Gas For $^6Li$ + $^2H$ => $^4He2$ Fusion?

It occurred to me that boiling $^6Li$ as the thermal step in a Z-pinch device, given lithium's low first-ionization energy, might be a better way of creating homogeneous ions for the subsequent ...
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### Question about the use of the term 'mode' vs 'instability' in fusion experiments

I am currently trying to get to grips with MHD instabilities in fusion experiments, and I am confused at to why instabilities are sometimes referred to as modes? To my understanding, a 'mode' is a ...
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### Magnetic tubes or magnetic field lines around a black hole?

A picture is worth thousand words: Magnetic field lines, unlike magnetic tubes, have a continuous distribution. Recent pictures of black hole magnetic structure show tubes. Is there a model that ...
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### Solving partial differential equations using MacCormack scheme and to quantify in what situations this scheme is stable using von Neumann stability

I am trying to simulate Alfven waves and for that, I need to solve partial differential equations using the MacCormack scheme. The predictor steps are: \begin{align} u^p_j&=u_j^n-c\left(b_{j+1}^n-...
1 vote
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### Ideal MHD energy transfer

Consider ideal MHD: infinite conductivity, frozen-in magnetic field lines etc. Clearly total energy of the system is conserved (magnetic field energy + plasma internal energy + kinetic energy = const)....
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### Dynamic of Alfvén waves in a hot magnetized plasma

I'm trying to derive the dispersion relation of Alfvén waves (AW) by solving analytically the Vlasov-Maxwell equations for a magnetized hot plasma but I'm confused. A simple question, to treat AW ...
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### Plage regions data

Plages are phenomena of stellar activity. Where can I find openly-accessible data of plage regions of the Sun with other parameters such as faculae region, magnetic field, etc?
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### Do drifting particles violate Alfvén's theorem?

According to this Wikipedia article, Alfvén's theorem states that "in a fluid with infinite electric conductivity, the magnetic field is frozen into the fluid and has to move along with it". ...
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### How to yield the relativistic equations of motion for a particle in a plasma non-dimensionless

The relativistic equations equations of motion for the ions are: $$\frac{d\vec{p}}{dt} \ = \ q (\vec{E}+ \vec{u} \times \vec{B}), \ \vec{p} \ = \ m \gamma\vec{v}$$ In many papers discussing test ...
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### Transition from inertial to kinetic range in Solar wind turbulence

Most papers studying the turbulence in the solar wind present figures showing the power spectral density (PSD) of the magnetic field. The inertial range, with a power law index of ~ -5/3, is followed ...
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