So, the 'excitation' part is due to the angular momentum imposed by traveling through the orthogonal magnetic fields
In the BASER the atoms of the Gain Medium are not traveling. They are stationary.
The primary excitation is through absorption of RF by the nuclei of the Gain Medium.
and the results are similar to electric field effects while traveling through the electric fields in a TEA laser?
There is some similarity in that the Gain Medium is transversely excited.
The polarizing/confining static magnetic field, the stimulating RF magnetic field and the velocity vector of the fast electrons are all mutually perpendicular to each other.
The main difference being instead of photons being produced the decelerating point charges exchange velocity for heat producing current?
In the BASER, fast electrons (or positrons) are produced instead of photons. The path of these fast electrons is circular in the Gain Medium, due to magnetic confinement (Lorentz deflection).
These electrons move close to the speed of light (~500keV) and they do not interact with the matter of Gain Medium even if it is a solid (unlike slow conduction electrons).
For example fast electrons travel without much interaction up to several millimeters in solids, before they slow down enough to be captured and and cause thermal vibration of the Gain Medium's lattice (resulting in Joule heating). See the attachment for non-directionalized paths of fast electrons in a solid.
Such fast electrons don't require a conductor and can even cross small air gaps. Nonetheless, these electrons still constitute electric current because they are traveling and directionalized charged particles (the very definition of current) - I like to call the directionalized and coherent stream of beta particles a "beta current".
Beta current produces magnetic field just like an ordinary current composed of slow conduction electrons. It is this changing magnetic field that can be inductively coupled to an output winding.
If so, there must be coherence between voltage/current phase. Are we talking about producing coherent current flow (p.f. = 1.00000) regardless of load?
There is some coherence. There is also a small delay between the stimulating RF pulse (an input) and the output pulse caused by the stimulated beta current.
Note that the beta current pulse destroys its own circular magnetic confinement field, by creating a magnetic field that opposes the confining static magnetic field and causing the expansion of fast electron's orbits out of the Gain Medium. This causes the output pulse to be self-quenching.
Inductive coupling of this output pulse (a removal of energy) maintains the confining field via Lenz law, thus drawing power prolongs the magnetic confinement and the output pulse with it.
I've built TEA lasers with amazing results but the lowest frequencies obtained were in the infrared region. It has occurred to me that the same principles could be used to produce RF, as seen in the so-called LENR experiments. I've always suspected the RF generating versions of LENR produced RF the same way a MASER produced microwaves. Theoretically, the signal generation bandwidth isn't limited.
The BASER does not have a low frequency limit, but it does have an upper frequency limit. This is because it takes a very specific amount of time to tilt the nuclear spin axes in the Gain Medium by 90deg.
Because of this the BASER's output is pulsed. A continuous operation would require an indefinite magnetic confinement and that would be explosive in nature since the beta current increases exponentially while the confinement is maintained. Fortunately the Gain Media has boundaries and beta current pulses are self-quenching.