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It's a blog! Mainly of book reviews.

Ursula K. Le Guin: Hainish Novels and Stories, Vol. 1: Rocannon's World / Planet of Exile / City of Illusions / The Left Hand of Darkness / The Dispossessed / Stories (The Library of America)

Progress:
87/1100 pages

Life and Letters of Charles Darwin - Volume 1: By Charles Darwin - Illustrated

Progress:
195/346 pages

Basics of Plasma Astrophysics

Progress:
3/250 pages

Ursula K. Le Guin: The Complete Orsinia: Malafrena / Stories and Songs (The Library of America)

Progress:
359/700 pages

Selected Short Stories - Conrad (Wordsworth Classics)

Progress:
236/272 pages

A Student's Guide to Lagrangians and Hamiltonians

Progress:
7/180 pages

Complete Poems, 1904-1962

Progress:
108/1102 pages

The Complete Plays and Poems

She Stoops to Conquer and Other Comedies (Oxford World's Classics)

Progress:
76/448 pages

Gravitation (Physics Series)

Progress:
48/1215 pages

So magnetohydrodynamics (MHD) is the (classical) theory of electrically conducting fluids, which divide neatly into liquid metals and plasmas. I'm not professionally interested in liquid metals so I skipped all the material that was solely applicable to them, which is possibly as much as half of it. It's also a microcosm of one of the many problems with the book -it's scope is way too large for it's size. To get anywhere with a topic that is defined as the merging of fluid mechanics and classical electrodynamics, one must have a thorough grounding in both those separate topics first. This book tries to cover that and does it badly because they need a book each. The physics of plasmas is very different from that of liquid metals but this book tries to cover both. So really we have four books' worth of material crammed into the space of only one. That's one problem.

Next there's the mathematical treatment, which is really poor. The subject requires a strong grasp of vector calculus. This is unavoidable. The fundamental equations of the theory are non-linear and form a large set that must be solved "self-consistently" whilst describing a dynamic (i.e. time varying) system. This also, is unavoidable. In other words this ain't no easy subject. That's no excuse for lax derivations, poor or absent definitions, or equations that are actually useless because one of the parameters in them has to be "chosen appropriately" (i.e. fudged) in every specific case, with no means of doing so so much as hinted at.

Finally, the verbal description of the physics is on occasions horrendously bad (and plain wrong). This is particularly so with regard to energy, which is repeatly "destroyed" throughout the book - a task nobody else has been able to accomplish in the history of physics. The author seems simply not to know what happens to the kinetic energy of the fluids he describes when it stops being obviously visible. Heat, man! Heat! Conservation of angular momentum is similarly and even more cavalierly treated.

I can't recommend this book to anybody, unfortunately.

I have a number of other books that treat MHD. In some it's an introductory chapter, in others it's in relation to a specific context (naturally occurring plasmas). Whether these will prove better remains to be seen.

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