 A follow-on design incorporating these changes would be both enormous and vastly more expensive than either JET or TFTR.A new period of pessimism descended on the fusion field.At the same time these experiments were demonstrating problems, much of the impetus for the US's massive funding disappeared; in 1986 Ronald Reagan declared the 1970s energy crisis was over, and funding for advanced energy sources had been slashed in the early 1980s.