Bringing the sun's spark to Earth and solving all energy concerns – that's what nuclear fusion promises. But will the new technology come in time for the energy transition, or will it come at all? Should Germany really invest billions, as the CDU, CSU and FDP, among others, are demanding? We asked American physicist Tammy Ma, who and her team claim to have recently made significant progress towards creating a fusion power plant. She says: How quickly we reach the goal is primarily a question of money.

Online time: Ms. Ma, a year ago, you and your colleagues surprised the world with an accomplishment of sorts. They crushed peppercorn-sized particles with a laser, releasing energy 1.5 times what the laser delivers. Can you tell us how something like this could happen?