Got it. Fiber lasers are now the new technology for theater defence/offence
up to 1 MW with wall plug efficiency >50%.
Thanks,
K
On Thu, Oct 15, 2020 at 1:59 PM Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
wrote:
Apply a potential difference to a conductive material, and you'll get a
net migration of electrons along the potential direction. "electric".
Oh, you wanted something more specific than that? :-) Current public
reports of tests and prototypes seem to cluster around what I presume are
diode lasers with continuous outputs in the tens of kilowatts range,
mounted with appropriate pointing and beam-forming on ships, aircraft, and
large ground vehicles. Some stories give the impression that the customers
think another order of magnitude of reliable power output (in the hundreds
of kilowatts) will give them a useful area defense against targets heavier
than the small rockets/shells and small drones commonly mentioned as
current test targets.
Henry
On 10/15/2020 1:48 PM, roxanna Mason wrote:
electric lasers these days.
Elaborate on "electric"
Ken
On Thu, Oct 15, 2020 at 1:41 PM Henry Vanderbilt <
hvanderbilt@xxxxxxxxxxxxxx> wrote:
Utility in evading missile defenses aside, one thing to keep in mind is,
for certain targets - among them ships - payload fraction is less
important. A hypersonic impact delivers TNT-equivalent energy for the
entire vehicle mass involved even with no actual warhead on board at around
Mach 9, and the equivalent energy of a 25%-of-vehicle mass TNT warhead at
Mach ~4.5.
Given that the main penetrating-defenses advantages seem to be
maneuvering beyond an interceptor's ability to follow, and operating in
atmosphere bands where the interceptor loses effectiveness, effective
anti-missile beam weapons will likely negate much of those advantages and
largely obsolete expensive hypersonics. Which may well explain why USN
(and USAF) seems very interested in electric lasers these days.
Henry
On 10/15/2020 2:23 AM, George Herbert wrote:
OT...
It’s not much of a secret I do missiles and nuclear proliferation research
and analysis including threat systems analysis as a side job.
There are a few things you can do with hypersonic weapons. You can approach
targets in the inconvenient altitude and speed band where there’s too little
lift for normal fins and too much for unstreamlined exoatmospheric
interceptors. Midcourse defense gets very difficult... You can change
direction in hypersonic flight, allowing flightpaths avoiding defenses or
attacking simultaneously from different directions, complicating defenses.
Under some circumstances they can use trajectory changes in target approach
to maneuver out of interceptor engagement envelopes after interceptor
burnout. Against rapidly maneuvering targets there is a better target
volume capability. Under some circumstances the range is longer than a
smaller ballistic trajectory Maneuvering Reentry Vehicle can do.
They are much more expensive and harder to do than maneuvering ballistic
RVs. They can’t carry effective decoys, IR sensors see them thousands of
kilometers away, and avoiding defenses has to be done essentially blind
because they can’t credibly detect incoming interceptors with onboard
sensors.
The payload fraction of ballistic RVs is about 0.5, of maneuvering RVs
0.3-0.4, of hypersonic glide weapons 0.2 or less and Hypersonic cruise
weapons 0.1 or so. For the same payload they’re tremendously larger
missiles to start with, with corresponding ship, aircraft, submarine, truck,
or silo capacity issues.
They make better sense as Chinese antiship Missiles than as US prompt
conventional strike missiles. The countries don’t have analogous needs.
-george
Sent from my iPhone
On Oct 14, 2020, at 10:19 PM, Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx>
<troy@xxxxxxxxxxxxxxxxxxxxx> wrote:
attracted a lot of attention and hype but had no military value
whatsoever.
(For the sponsoring nation, that is -- it had considerable value to their
enemies,
since it pulled desperately-scarce resources away from things that *did*
have
real military value.) The recent hypersonics hype smells much the same to
me...
Henry
I guess the difference now is the "enemy/ies" are all on the same hypersonic
bandwagon.
Troy