Jeffrey Scott Shapiro asks in a recent WSJ op-ed ('UFOs May Be Earthly And Dangerous', p. A 13):
"Have space aliens been visiting Earth? That’s the wrong question to be asking about UFOs—or, as they’re now officially called, unidentified aerial phenomena or UAP."
Given a collisionless plasma, the Vlasov-Boltzmann equation will apply, for which the governing equation is:
v ¶ f x/ ¶ x - q(s)/m(s) [¶ j/ ¶ x · ¶ f s/ ¶ v] = 0
And said dissipation can be attributed to Landau damping and this may be the most common form to also excite a shock that incites incoherence in the plasma. This incoherence would destroy any "plasma UFOs" way before they show up on a Navy pilot's target screen or indeed, any radar. Or "produce enough physical particles" to imitate a real craft crashing into the sea then emerging again. Shapiro speculates such technology "may or may not be operational". I can assure him at the scales of energy needed to pull off this "confusion" for dozens of different objects at different rates of speed, g forces etc, it is not.
Recall in Landau damping - given the energy balance equation:
S Etot = ½ E1 w + E1 k = ½[ ½ eo | E1|2] + ½ r | ṽ|2
g L = (p/ L) w e 3 / k 2 [g' (v f )]