Apparently the toroidal ring has some property that allows it to reduce the energy requirements. "and in particular a ring around it that is key to its propuls

Apparently the toroidal ring has some property that allows it to reduce the energy requirements. "and in particular a ring around it that is key to its propulsion system — in a way that he believes will greatly reduce the energy requirements" http://www.nytimes.com/2013/07/23/science/faster-than-the-speed-of-light.html?pagewanted=all&_r=0 http://www.nytimes.com/2013/07/23/science/faster-than-the-sp...