A novel method to determine the total hydrogen density and, accordingly, a precise plasma temperature in a lowly ionized hydrogen plasma is described. The key to the method is to analyze the energy ...loss of swift heavy ions interacting with the respective bound and free electrons of the plasma. A slowly developing and lowly ionized hydrogen theta-pinch plasma is prepared. A Boltzmann plot of the hydrogen Balmer series and the Stark broadening of the H_{β} line preliminarily defines the plasma with a free electron density of (1.9±0.1)×10^{16} cm^{-3} and a free electron temperature of 0.8-1.3 eV. The temperature uncertainty results in a wide hydrogen density, ranging from 2.3×10^{16} to 7.8×10^{18} cm^{-3}. A 108 MHz pulsed beam of ^{48}Ca^{10+} with a velocity of 3.652 MeV/u is used as a probe to measure the total energy loss of the beam ions. Subtracting the calculated energy loss due to free electrons, the energy loss due to bound electrons is obtained, which linearly depends on the bound electron density. The total hydrogen density is thus determined as (1.9±0.7)×10^{17} cm^{-3}, and the free electron temperature can be precisely derived as 1.01±0.04 eV. This method should prove useful in many studies, e.g., inertial confinement fusion or warm dense matter.
Intense heavy ion beams from the Gesellschaft für
Schwerionenforschung (GSI, Darmstadt, Germany) accelerator facilities,
together with two high energy laser systems: petawatt high energy laser
for ...ion experiments (PHELIX) and nanosecond high energy laser for ion
experiments (NHELIX) are a unique combination to facilitate pioneering
beam-plasma interaction experiments, to generate and probe
high-energy-density (HED) matter and to address basic physics issues
associated with heavy ion driven inertial confinement fusion. In one class
of experiments, the laser will be used to generate plasma and the ion beam
will be used to study the energy loss of energetic ions in ionized matter,
and to probe the physical state of the laser-generated plasma. In another
class of experiments, the intense heavy ion beam will be employed to
create a sample of HED matter and the laser beam, together with other
diagnostic tools, will be used to explore the properties of these exotic
states of matter. The existing heavy ion synchrotron facility, SIS18,
deliver an intense uranium beam that deposit about 1 kJ/g specific
energy in solid matter. Using this beam, experiments have recently been
performed where solid lead foils had been heated and a brightness
temperature on the order of 5000 K was measured, using a fast
multi-channel pyrometer that has been developed jointly by GSI and IPCP
Chernogolovka. It is expected that the future heavy ion facility, facility
for antiprotons and ion research (FAIR) will provide compressed beam
pulses with an intensity that exceeds the current beam intensities by
three orders of magnitude. This will open up the possibility to explore
the thermophysical and transport properties of HED matter in a regime that
is very difficult to access using the traditional methods of shock
compression. Beam plasma interaction experiments using dense plasmas with
a Γ-parameter between 0.5 and 1.5 have also been carried out. This
dense Ar-plasma was generated by explosively driven shockwaves and showed
enhanced energy loss for Xe and Ar ions in the energy range between 5.9 to
11.4 MeV.
Intense ion beams from accelerators are now available to generate high energy density matter and to study astrophysical phenomena in the laboratory under controlled and reproducible conditions. A ...detailed understanding of interaction phenomena of intense ion- and laser radiation with matter is important for a large number of applications in different fields of science, extending from basic research of plasma properties to application in energy science and the investigation of processes occurring in stellar atmospheres or even in the interior of stars and planets. Energy loss processes of heavy ions in plasma and cold matter are important for the generation of high energy density states in general and especially in the hot dense plasma of an inertial fusion target. Of special interest are phase transitions and the associated time scales when matter passes the warm dense matter regime of the phase diagram at high density but relatively low temperature. We present an overview on recent results and developments of beam plasma, and beam matter interaction processes studied with heavy ion beams and laser beams combined with accelerator and nuclear physics technology. A natural example of hot dense plasma is provided by our neighbouring star the sun, and allows a deep insight into the physics of fusion, the properties of matter at high energy density, and is moreover an excellent laboratory for astroparticle physics. As such the sun’s interior plasma can even be used to probe the existence of novel particles and dark matter candidates with a combination of equipment and methods from accelerator technology and high resolution plasma spectroscopy.
Cylindrical cryogenic targets are required to carry out the Laboratory Planetary Science scheme of the experiments of the High Energy Density matter Generated by Heavy Ion Beams collaboration at ...FAIR. In this paper, for the first time a thorough analysis of the problem of such targets' fabrication, delivery and positioning in the center of the experimental chamber has been made. Particular attention is paid to the issue of a specialized cryogenic system creation intended for rep-rate supply of the High Energy Density matter Generated by Heavy Ion Beams experiments with the cylindrical cryogenic targets.
We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heated with an intense pulse of heavy ions. In this way, we ...determine the samples’ heating dynamics and their microscopic and macroscopic structural integrity over a timespan of several microseconds. Connecting the ratio of elastic to inelastic scattering with state-of-the-art density functional theory molecular dynamics simulations allows the inference of average temperatures around 1300 K, in agreement with predictions from stopping power calculations. The simultaneous diffraction measurements show no hints of any volumetric graphitization of the material, but do indicate the onset of fracture in the diamond sample. Our experiments pave the way for future studies at the Facility for Antiproton and Ion Research, where a substantially increased intensity of the heavy ion beam will be available.
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