Deep-space communications relay stations

[Billy T]

If that's the case then what you said is certainly not true. If it takes a significant time to vaporize (i.e. over a few hundred milliseconds) then you are not vaporizing a surface layer - you're melting the thing by pumping heat into it.

The one time the 'vaporization' effect becomes useful is if you can pump so much energy into the beam that the surface vaporizes instantly, generating a rapidly expanding cloud of gas (i.e. a violent explosion.) The shock wave then compresses the structure near it and destroys the object.

I did not say "vaporization" or mention shock waves or any "cloud of gas" or speak of a "few hundred milliseconds" etc. I said in post 77:
"... boil off the surface layer into the vacuum of space with well focused high powered laser ..."

I do agree that if you could produce an explosion of vaporizing metal gas with shock wave propagating back into the target, you could have significant damage to the target; however, I said the Air Force attempts to damage the target were "not very successful."

Thus only "boiling into vacuum" some relatively few atoms of the surface is what happened. Nothing like what you describe and very far from the attempts to get nuclear fusion via "inertial confinement." I.e. no "gas cloud" but the "vacuum of space" is what I spoke of.

Furthermore, I mentioned the closed loop tracking system which kept the invisible IR beam on the small white hot spot of the target - That implies seconds, not milliseconds, and in fact they were able to hold the beam on the same target spot for seconds. (I probably should not give a number - I have had classified information on this Air force program.)

A liquid “boils” when the highest velocity atoms/molecules of it can overcome the surface binding energy* AND the rate of their return from the space above the liquid surface is less than the rate they are escaping from the surface. (I.e. there is net loss of mass from the boiling liquid.) Boiling can thus be a much less violent process than the “explosive vaporization” you misunderstood me to be speaking of. For example when exposed to the vacuum of space (which I did speak of) room temperature water will boil, by this definition of boiling. The Air force was able to make surface “pits” but not holes in the target wall – nothing like you are suggesting. (I said "not very successful.")

Not even close. The target wall will always be much, much thicker than skin depth. … For microwaves it's ~50 micrometers (for aluminum.) In both cases the actual thickness of any reasonable spacecraft skin is going to be at least an order of magnitude thicker (i.e. a millimeter at least.) To get skin depth to come close to the thickness of the material you'd need frequencies of 10KHz or so.

I don’t think that correct, but don’t know what wave length you are calling “microwaves”

To get the high power beams we are speaking with current microwave technology (such as the Aegis ships use – they are the most powerful microwave source that exists AFAIK), the wave length will not be very significantly shorter than 10 cm. (say at least 3 cm).

Of course the skin depth depends on the conductivity of the metal but crudely speaking, as I recall, the skin depth is always at least one 1/10th of the wave length. My memory here was wrong. You are basically correct - more reason why only a very thin surface layer was pitted.
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* "Surface binding energy" is closely related to, if not identical with, the "surface tension."