From the Begining New Chapter Added (9/12/06)

[Hunpecked]

El_Phil writes: "Large magazine for a railgun or huge reactors, inductors, cooling systems for energy weapons. Hmmmm...."

If you're putting comparable energies on the target--whether "energy beam" or kinetic energy projectile--don't you need to control comparable energies at the source? For example, doesn't the railgun require a substantial "reactor" to generate the current for something like 3 million G's on its projectile (assuming its velocity of 0.1c is attained in one second or less)? If it's less than 100% efficient, it will also require cooling. I'm no engineer, but I suspect it would also require massive conductors, inductors, transformers, etc.

[El_Phil]

True, but you aren't messing around with exotic particles. This vastly simplifies the entire process and reduces the losses in conversion (as there are less converions ).

Also although the total energy is the same, the peak would be lower. A 100TW beam would need a 100TW reactor to power it when it's firing. A magneic accelerated railgun slug builds up its KE over the course of its acceleration. So a 10TW reactor powers the magnets for 10 seconds and you've put the same amount of power into the final weapon, but with a reactor 10 times smaller. Or you use the same size reactor and get a 10 times more powerful weapon.

[Hunpecked]

El_Phil writes: "So a 10TW reactor powers the magnets for 10 seconds and you've put the same amount of power into the final weapon, but with a reactor 10 times smaller."

To accelerate a projectile to 0.1c in 10 seconds, the railgun would have to be about 150,000 km long. By comparison, the average earth-moon distance is about 384,000 km.

A railgun that could do the job in 1 second would be "only" about 1500 km long, but of course it would require 10 times the reactor capacity.