I don't claim to have The Answer, but here's how I sorta reconciled all the
various aspects and descriptions of the jump drive.

First, there is textev for the following components for the Jump Drive:

1. The Drive itself. This is a big bulky piece of equipment that we know
   for sure has...
2. ...Jump Coils in it. There are also associated with it...
3. ...Zuchai Crystals, and...
4. ...Jump Capacitors.
5. There is also a "Jump grid" embedded in the hull, of which Lanthanum is
   a component. Except in some older Vargr implementations, which use
   Barium instead.

We also know that 'fuel' is used in large quantities. Very large
quantities. This 'fuel' is canonically liquid hydrogen.

OK, here's my take on what happens, step by step:

0. INFORMATION: The Jump Drive's four most important components are [in no
   particular order] (a) a Big Honking Handwavium-based Reactor (BHHR),
   (b) the Zuchai Crystals, (c) the Jump Coils, which in some designs
   surround the Zuchai crystals and in others are surrounded by the
   crystals, and (d) the Jump Capacitors

1. The course is programmed into the computer. This causes some field
   and/or beam generators surrounding the Zuchai crystals to align
   themselves and set prospective power levels, and also sets a sequence of
   changes therein. If there is a jump grid, it also specifies energization
   levels and sequences for the segments of the grid.

2. When the command to jump is given, the BHHR goes into operation at its
   maximum possible rate. This causes energy to be generated.

3. Most of this energy is sent to the Capacitors for storage. The
   capacitors can take in the energy at least as fast as the BHHR can
   generate it. A comparatively small amount is diverted to the field and
   beam generators.

4. The fields and beams interact with the Zuchai crystals as described in
   the General Field Theory of Mumble and Inaudible. This generates a
   spherical field potential - not yet an actual field - around the ship.

5. If there is a jump grid, its various segments are energised per the
   computer instructions. This allows the field potential to be reshaped to
   conform more closely to the ship's surface.

6. The fully-charged capacitors discharge into the Jump Coils. This causes
   the field _potential_ to become an actual field that "opens" a "hole"
   from normal space into the non-space called jump space. The hole almost
   immediately closes, but the ship is now in jump space. The duration and
   exit point of the jump are now committed; the only thing that can change
   them is a failure of the field - which will destroy the ship.

7. The BHHR is 'stepped down' to provide a low level of energy to keep the
   field and beam generators and the jump grid energised, and thus
   maintaining the field. This prevents jump space from interacting with
   the matter of the ship, which is fatal to the matter.

8. At the appointed time, the field, which has been receiving a steady
   input of energy, "pulses" entirely out of the control of the ship. This
   opens the hole back to normal space, and when it closes (again, almost
   immediately), the ship is back in normal space. The field and beam
   generators and the jump grid de-energise, and the field and field
   potential drop to null. Jump is complete.

Articles like my Color of Jumpspace suggest that the statement about
commitment in 6. above may not be entirely accurate, and it says nothing
about whether there is a hydrogen "bubble" within the field and around the
ship (but perhaps that's a 'safety' feature, on the theory that if there's
a field failure, _maybe_ having the hydrogen 'protecting' the ship itself
will give the crew a chance to restore the field before jumpspace interacts
with the hull itself...). Or maybe the jump engineer that explained it to
me dumbed it down a bit too much, and it's oversimplified. Or something.

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