Shahriar Badiei

Experimental studies of fast fragments of H Rydberg matter

A comprehensive pulsed-laser time-of-flight (TOF) study of H Rydberg matter (RM) fragments is presented. The nature of the fragments released with well-defined kinetic energies of 9–24 eV is investigated: the detected fragments are found to be H* in Rydberg states with principal quantum number n > 28. The only way to produce such states is from Coulomb explosions in a pre-formed easily laser-fragmented molecular entity. Non-symmetric angular distributions of the fragments are measured and Coulombic shockwave phenomena are observed, which prove that the phase of origin is not a gas but an RM phase. The fast particles are concluded to be formed in two-, three- and four-particle Coulomb explosion processes in an H RM cluster. Laser intensity variation measurements indicate that between four and six photons with a total energy of 8.8–13 eV take part in the RM fragmentation. This proves that laser-induced processes in H2 or H2+ molecules, even in the RM phase, are excluded for energetic reasons. A feasible H RM formation mechanism is deduced from the signal variation with H2 pressure, with the dissociation of H2 on the emitter surface as the rate limiting step. The principal quantum number of H Rydberg species H* reaching the detector is estimated to be n > 32 from a comparison of the calculated ionization rate of the H* species in the electric field inside the detector with measurements.

Production of ultradense deuterium: A compact future fusion fuel

Ultradense deuterium as a nuclear fuel in laser-ignited inertial confinement fusion appears to have many advantages. The density of ultradense deuterium D(−1) is as high as 140 kg cm−3 or 1029 cm−3. This means that D(−1) will be very useful as a target fuel, circumventing the complex and unstable laser compression stage. We show that the material is stable apart from the oscillation between two forms, and can exist for days in the laboratory environment. We also demonstrate that an amount of D(−1) corresponding to tens of kilojoules is produced in each experiment. This may be sufficient for break-even.

Neutral Rydberg matter clusters from K: extreme cooling of translational degrees of freedom observed by neutral time-of-flight

Abstract Neutral electronically excited clusters KN* with N=2–7 are formed and studied by neutral time-of-flight (TOF) caused by laser induced Coulomb explosions in a cloud of Rydberg Matter (RM). A thermal velocity distribution would give TOF peaks with widths of the order of 100 μs . Instead, the minimum half-width is 5 μs , indicating supersonic velocities with an effective temperature of

Stimulated emission in Rydberg Matter – a thermal ultra-broadband tunable laser

Abstract A tunable laser is built with the condensed excited material Rydberg Matter as the active medium. It is tunable over at least 0.9–16 μm in the infrared. The tuning is almost continuous over this range, due to the broad bands for the forbidden transitions in Rydberg Matter. The beam divergence is low,

Experimental observation of an atomic hydrogen material with H–H bond distance of 150 pm suggesting metallic hydrogen

A phase of hydrogen Rydberg matter (RM) is formed in ultra-high vacuum by desorption of hydrogen from an alkali promoted RM emitter (Holmlid 2002 J. Phys.: Condens. Matter 14 13469). The RM phase is studied by pulsed laser-induced Coulomb explosions which is the best method for detailed studies of the RM clusters. This method gives direct information about the bonding distances in RM from the kinetic energy release in the explosions. At pressures >10−6 mbar hydrogen, H* Rydberg atoms are released with an energy of 9.4 eV. This gives a bonding distance of 150 ± 8 pm which corresponds to a metallic phase of atomic hydrogen using the results by Chau et al (2003 Phys. Rev. Lett. 90 245501). The results indicate that a partial 3D structure is formed.