by chuck » Mon Feb 11, 2008 7:38 pm
You are confusing energy with power. 64 Megajoules is a measure of energy. 40 gigawatts is a measure of power. Energy is power integrated over time. Like a normal gun, a railgun delivers high peak power, but sustains that peak power for only a tiny length of time, so the power is high but the total energy delivered is really quite modest. Have an hour to deliver 64 MJ, and you only need to deliver it at a rate of about 17 Kilowatts. Have a nanosecond in which to deliver 64 MJ, and you will need to deliver it at a rate of about 6 quadrillion watts.
In fact the total energy, 64MJ, delivered by a rail gun is 1 order of magnitude less than the energy delivered by a WWII era 16" gun. The peak power delivered by the rail gun is roughly comparable to those developed by a 16" naval gun. If you accumulate all the energy generated by running Chicago's 19GWs of generators for 1 hour, you can fire that rail gun over 1 million times.
You are confusing energy with power. 64 Megajoules is a measure of energy. 40 gigawatts is a measure of power. Energy is power integrated over time. Like a normal gun, a railgun delivers high peak power, but sustains that peak power for only a tiny length of time, so the power is high but the total energy delivered is really quite modest. Have an hour to deliver 64 MJ, and you only need to deliver it at a rate of about 17 Kilowatts. Have a nanosecond in which to deliver 64 MJ, and you will need to deliver it at a rate of about 6 quadrillion watts.
In fact the total energy, 64MJ, delivered by a rail gun is 1 order of magnitude less than the energy delivered by a WWII era 16" gun. The peak power delivered by the rail gun is roughly comparable to those developed by a 16" naval gun. If you accumulate all the energy generated by running Chicago's 19GWs of generators for 1 hour, you can fire that rail gun over 1 million times.