Robert’s Reviews > An Introduction to Magnetohydrodynamics > Status Update

Skipped the stuff on the geo-dynamo (origin of Earth's magnetic field) - interesting but not urgent. Alfven waves are qualitatively straight-forward; imagine plucking magnetic field lines like they are guitar strings! Of course the field must be embedded in a moving plasma. Magnetostrophic waves on the other hand, are clear as mud. They can occur when the magnetic field is rotating in relation to the plasma.

I skipped the material specific to liquid metals as it is not relevant to my interest (plasmas).

The presentation remains bad but I've just come across a possible explanation of the ionospheric phenomenon of "(magnetic) field-aligned irregularities."

"...efficient method of destroying energy." Anybody who's done school physics knows that's just plain wrong. In this case the rotational kinetic energy of the fluid is being converted to heat or at least to small scale turbulent flow (ultimately because the fluid is viscous). (The example is why the vortex you create by stirring a cup of tea disappears so fast when you remove the spoon!)

Yep, gonna need to find a better book than this one.

If I read "...a characteristic scale length, l," without any explanation of how to determine such a length in any specific case one more time, I am liable to scream. This isn't an isolated problem; undefined terms are popping up all over the place. The author also appears to have missed a subtle point about vorticity in fluid flows, namely it totals to zero even in a turbulent flow, unless there is external stirring.

I can't remember any other book deteriorating so rapidly from an excellent start...the issue (besides the typographical problems) seems to be that the author can give a good verbal description of what is going on but the mathematical presentation is awful. Even the verbal part is flawed by the use of undefined terms, however.

OK, no; the "derivation" of the appropriate electrodynamic equations just states stuff without proof or any indication of how to proceed by oneself. That's crap textbook writing (but all too common).

After some revision of classical electrodynamics, this is beginning to look tractable, though not easy.

The first mathematical treatment is basically incomprehensible; this bodes ill for the remainder of the book.