MeV particles from laser-initiated processes in ultra-dense deuterium D(-1)

Fast particles from laser-induced processes in ultra-dense deuterium D(-1) are studied. The time of flight shows very fast particles, with energy above MeV. Such particles can be delayed or prevented from reaching the detector by inserting thin or thick metal foils in the beam to the detector. This distinguishes them from energetic photons which pass through the foils without delays. Due to the ultra-high density in D(-1) of 1029cm-3, the range for 3 MeV protons in this material is only 700 pm. The fast particles ejected and detected are thus mainly deuterons and protons from the surface of the material. MeV particles are expected to signify fusion processes D+D in the material. The number of fast particles released is determined using the known gain of the photomultiplier. The total number of fast particles formed, assuming isotropic emission, is less than 109 per laser pulse at < 200 mJ pulse energy and intensity 1012W cm-2. A fast shockwave with 30keV u-1 kinetic energy is observed. (orig.)