Graser replacement

namelessfly wrote:It is a reasonable inference from basic fusion reactor physics.

The gravity containment system has to not only contain the hot plasma but the fusion reactor products.

I am assuming that the reactor plasma is not large enough and dense enough for the fusion reaction products to be thermalized to the lower average energy before reaching the reactor vessel walls. Since even the "clean" fusion reactor fuels (whose fusion reaction cross sections are small relative to D-T and D-D retains and thus their power density sucks) have sideband reactions that produce Neutrons, your reactor containment field needs to create a deep enough gravity well to shield the reactor walls. If not your missile will transform itself into radioactive slag.

This assumption is validated by the gravity focusing of fusion explosions in laser heads. Even if the fuel burn fraction of the explosive device is on the order of only 10%, you still getba plasma with a characteristic velocity of 1eex7 m/s. It takes a very steep gravity well to contain that.

Jonathan_S wrote:Even if you give the mass driver the seemingly ludicrous ability to impart 1,000,000 m/s velocity; at 6.8 Mkm the ship launched missiles only get there about 2.35 seconds sooner. Alternatively you'd need to step down the ship-launched missiles by about 1,140 g (to 41,865g) to achieve time on target with pod launched missiles. Compared to what the shipboard missiles would do, with that high initial velocity and 50% power (43,000g), they'd now have 2.6% lower terminal velocity, the pod based missiles only 1.3% lower terminal velocity. (That's giving the pod launched missiles no initial velocity and 50% power)


Doesn't seem like a significant difference, from even a quite high initial velocity.

Jonathan_S wrote:That gives the impression that the difference is significant, even in a missile that's capable of reaching around 76,000 KPS in 180 seconds. [I'm number crunching with OBS era single-drive missiles, 43,000g at their 50% power max-range settings]
...
Doesn't seem like a significant difference, from even a quite high initial velocity.

Tenshinai wrote:

Jonathan_S wrote:That gives the impression that the difference is significant, even in a missile that's capable of reaching around 76,000 KPS in 180 seconds. [I'm number crunching with OBS era single-drive missiles, 43,000g at their 50% power max-range settings]
...
Doesn't seem like a significant difference, from even a quite high initial velocity.

Well, the missiles can´t start their engines up properly until they´re outside the wedge of the launching ship can they? Wedges that stretch several km...

Meaning that the comparison isn´t with the missile´s own acceleration, but with how long it takes before the missile can turn it´s own wedge up and running to get that acceleration.

SWM wrote:

namelessfly wrote:It is a reasonable inference from basic fusion reactor physics.

The gravity containment system has to not only contain the hot plasma but the fusion reactor products.

I am assuming that the reactor plasma is not large enough and dense enough for the fusion reaction products to be thermalized to the lower average energy before reaching the reactor vessel walls. Since even the "clean" fusion reactor fuels (whose fusion reaction cross sections are small relative to D-T and D-D retains and thus their power density sucks) have sideband reactions that produce Neutrons, your reactor containment field needs to create a deep enough gravity well to shield the reactor walls. If not your missile will transform itself into radioactive slag.

This assumption is validated by the gravity focusing of fusion explosions in laser heads. Even if the fuel burn fraction of the explosive device is on the order of only 10%, you still getba plasma with a characteristic velocity of 1eex7 m/s. It takes a very steep gravity well to contain that.

I see. Unfortunately, I don't agree with your assumptions.

Lord Skimper wrote:Always wondered if you could fuse with fusion then split them a part and repeat?

Lord Skimper wrote:Always wondered if you could fuse with fusion then split them a part and repeat?

namelessfly wrote:Fair enough.

I would be curious to know what your assumptions are regarding how steep the gravity well for a fusion reactor would be. Even if the fusion reaction produced no neutrons, the charged nuclei of the fusion reaction products would require time and distance to be thermalized with the reactants.