Plasma devices to guide and collimate a high density of MeV electrons

The development of ultra-intense lasers 1 has facilitated new studies in laboratory astrophysics 2 and high-density nuclear science 3 , including laser fusion 4 , 5 , 6 , 7 . Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser–matter interactions at petawatt (10 15 W) power levels can create pulses of MeV electrons 8 , 9 , 10 with current densities as large as 10 12 A cm -2 . However, the divergence of these particle beams 5 usually reduces the current density to a few times 10 6 A cm -2 at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser–matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.