On the subject of why the warp engines have to be so far away from the power-generating reactor in the interpretation where the engines themselves aren't power-generating potential bombs...
Perhaps it's in some ways analogous to the relationship with seagoing ship powerplants and propellers again? Those generally aren't in the same place due to concerns about the center of gravity: the long propeller shafts (or the long hydraulic leads, in case the props are on rotating pods) are there to allow the massive power systems, and to some degree their fuel stores, to be placed close to ship centerpoint.
In the Star Trek case, it could be that the reactor isn't particularly massive yet the fuel sources still are. The nacelles have to be in an outlying position for the same reason the propellers are: their function calls for exposure. But a stability concern of some sort, perhaps relating to impulse drive, calls for the fuel tanks to be at the very center of the ship. That's where their constantly changing (that is, decreasing) mass will have the least effect on stability, at any rate.
Once that's decided, the accessibility issues are in synch with the need to have the reactor close to the fuel in its volatile antimatter form; the leads of the less dangerous plasma can be made longer to compensate.
Not that all known starship designs would conform. But we don't have blatant counterexamples of the fuel being far away from the reactor, either - except perhaps in the Oberth class, in the model that has the reactor up in the primary hull and the fuel down in the pod. (And that's not the model that the Okudagrams support, to be sure.)
One of your posts has swayed my opinion yet again Timo. Captain Robert April also makes a sound argument. I suppose the benefits of a central power core combined with drive units well clear of the inhabited parts of the ship more than counter any disadvantage that relatively long plasma conduits might have.
I wasn't aware that the plasma was accelerated
in the conduits Kent. This would be a great rationale for their length on it's own. I also have to admit to never having seen reference to any subspace effects being involved with any part of the drive system before the plasma transfers energy to the warp coils in the nacelles, though your theory(s) certainly sound interesting.
no you're right there isn't any direct on screen evidence. but i would like to point out that other than the unsupported treknobabble there really isn't any direct anything that explains warp drive anyway.
The plasma would have to in some way be prepped to create the subspace fields emitted by the warp engines. to say that it's just plasma that's accelerated by the warp reaction chamber would be a little odd considering all elements of the warp drive power creation have to be related in some way.
That said, the only way I can feesibly ration that the dilithium doesn't mutually annihilate is that it's somehow related to subspace on it's own, thus altering the plasma itself into a partially phased subspace state, where it's further accelerated on it's way to the warp nacelles, prepped to interact with the warp coils materials that are known to interact with subspace.
If it was just the nacelles themselves that interact with subspace, then they would have to have inherent properties themselves which relate to subspace. At least that's my rational when the dilithium itself doesn't mutually annhilate. If it was some other way, like the matter and antimatter reacting with say a dark matter pocket which has no detectible mass, then that resulting radioactive plasma is sent through the conduits to the warp nacelles in which the coils materials interact with this new type of energy combined of a dark matter, positive matter, and antimatter reaction, then I could see the warp nacelles being the direct creators of the warp subspace fields themselves.
But that's not the case. Instead we have a material of positive matter, the dilithium, that seemingly doesn't annhilate when antimatter and matter touches it. No. Instead when the matter and antimatter mutually annihilate (I have no idea if i'm spelling that right lol.), it causes a reaction via the dilithium. This reaction creates the nacelle ready plasma. Why would there be a reaction with the dilithium in the first place if it didn't have some purpose in creating the fields? Why does there have to be dilithium at all at that point? Why not a simply very powerful explosion in which the energy is transferred through the conduits to the nacelles? The reason is the dilithium serves as an alteration or preparatory device that allows the nacelle interaction with the plasma to create warp fields.
And they aren't gravitational fields, they are subspace fields that somehow warp space around the ship to allow travel through subspace while still somehow emerged in our own space (case in point, the ship is travelling through subspace yet we still see things in our own level of space. Hence the phasing of the dilithium.). Even a planet as big as Earth doesn't create gravitational forces on the level of warping space on that effect. It would have to be something akin to a black hole's level of space warping.