[CraigD]

Originally Posted by silverslith

I think the logic of the trapped Plasma in the field bubble is to provide a friction force and for ionisation for the uncharged particles and a friction to slow down the charged particles that are trapped by the field.

Possibly. The dynamics seem complicated, and not clearly described in the BBC article. The original literature my be more clear.

Neutrons are pretty rare and do little damage as they go right thru you with little chance of a collision.

I think you’re confusing neutrons and neutrinos.

Neutrinos are very common (the Sun produces about , nearly 100000 times the number of solar wind particles), but so weakly interacting that they’re almost impossible to detect.

Neutron radiation is a major kind of potentially dangerous radiation. It’s associated with both nuclear fission and fusion, and is responsible for the nuclear fission chain reaction. It’s very dangerous to biological life, a characteristic exploited by the neutron bomb, a type of “enhanced” fusion (“H”) bomb that kills while doing comparatively little physical damage. Neutrons induce radiation in target atoms, and can transform target atoms into radioactive isotopes, as well as damage crystal structures, causing materials to become brittle or “swollen”. They’re more difficult to shield against than electrons and neutrons, requiring many light atoms (eg: H2O) rather than few heavy ones (eg: lead shielding). Unfortunately, most plant and animal tissues are good neutron shields, so neutrons can penetrate ordinary radiation shielding (eg: lead aprons), preferring the human being behind it.

Fortunately photon radiation won't be affected by the crafts velocity and its much easier to shield with a hull than high energy protons which are by far the largest hazard. Gamma and xrays are much lower in flux density out there anyway.

True, but the hazards of uncharged particles – non-ionized atoms, dust grains, or even the occasional large body shouldn’t be ignored.

I can’t see how magnetic shielding can work without some sort of ionizing system, such as powerful lasers – unless the magnet is so strong it can ionize neutral atoms (strip them to plasma).

[silverslith]

cheers Craig.
Your right, neutrons are best absorbed by protons in hydrocarbons or water. Still at decent energies they mostly pass through stuff as dense as u238 metal 7cm thick without hitting anything at all. Interesting physics with this in nuke bombs. While the tamper-a shell of 10cm thick 238 would normally let most escape, the pressure vs inertia compresses them to several times the normal density making them far better neutron reflectors, and providing often more energy than the core through fast neutron fission. The deuterium in an H bomb also provides less energy, mainly being a neutron multiplier for an outer u238 shell.
Neutrinos are far more common in space and thank the creator of our universe they don't affect much at all, passing through the earth with only small percentage losses.

[Gardamorg]

This is a what if question.

Say for some reason the IPCS had to use all of its fuel when it had been out of orbit for 5 days (Everything that the nuclear reactor could produce in 5 days) and go as fast as it could. How fast would it go?


I know that its a stupid question, but its on topic and I have to get my post count up.

[silverslith]

Originally Posted by Gardamorg

This is a what if question.

Say for some reason the IPCS had to use all of its fuel when it had been out of orbit for 5 days (Everything that the nuclear reactor could produce in 5 days) and go as fast as it could. How fast would it go?


I know that its a stupid question, but its on topic and I have to get my post count up.

OK. by out of orbit, what is meant?
1.) on the surface of an earth like planet, lets say earth for arguements state.
2.) in interplanetary space.
3.) in interstellar space.
Now assuming that burning all your energy and having no way to make more is not the situation as its a very bad situation to put yourself in:
1.) The reactor is reved up with protons from an internal storage loop and injected with a near critical mass of actinides kept available for energetic proton scarce situations. Or hafnium batteries are used if the technology has matured. The force from EM thrust against earths field is assumed to be at worth at least 1g acceleration within the earths magnetosphere as this is well within current superconducting technologies. So 36000m/s or130000 kmph, less gPE is achieved after one hour, ~0.5-1million kmph by leaving the magnetosphere in 5 hrs. If its a bigger planet with a stronger magfield more to a lot more. We don't land on silly little planets with no magfield, they are not worth the effort.
2.) we don't hang around in interplanetary space. If we are there we are going somewhere else. If we are going fast enough we can use solar wind protons scooped by the magfields as well as internal stores and actinide backups to rev our reactor and stock our fast particle stacks. Within an hour we can launch at crew bearable g's in whatever direction. (hopefully). Driving through dust belts and radiation belts will help pick up fuel and reaction mass if we are short.
3.) We are going at over 30 000 km/s probably close to 300 000 000 km/s. We are impatient folks and don't like to waste time between star systems. We would not be there without sufficient high energy particle stacks to stop and these are also the loud pedal for our reactor. Also at that velocity, interstellar protons are fast and ready to be scooped into our reactor. Any junk lying round the ship could be processed by the reactor and turned into highly energised thrust particles.

[Gardamorg]

Ok, thanks for answering.

[silverslith]

No problem. I enjoyed it. Talking to myself is boring.