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Volume 41, Issue 1
Topical Papers on Invitation for High Energy Density Science
Displaying 1-11 of 11 articles from this issue
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Topical Papers on Invitation for High Energy Density Science
Topical Paper
Laser Review
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Ryosuke KODAMA2013 Volume 41 Issue 1 Pages 4-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSDownload PDF (281K) -
Hideaki HABARA, Tomoyuki IWAWAKI, Toshinori YABUUCHI, Kazuo TANAKA2013 Volume 41 Issue 1 Pages 7-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSUltra intense laser (UIL) light can create relativistic plasmas whose electron oscillation energy exceeds the electron rest mass. The interaction of such relativistic plasma with UIL exhibits distinct relativistic effects such as relativistic self-focusing or relativistic transparency as well as very rich nonlinear effects such as relativistic fi lament instability or stimulated Raman scattering. In addition to the brief review of these phenomena, we describe the channel creation and the anomalous penetration by UIL (superpenetration) as an application of relativistic plasma.View full abstractDownload PDF (1381K) -
Motoaki NAKATSUTSUMI2013 Volume 41 Issue 1 Pages 13-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSHigh-energy-density plasmas generated by intense-laser pulses allow the control of light, through processes such as reflection, focusing, amplification and frequency conversion. Many of these applications have been recently demonstrated. These plasma-based optical devices are compact, functional and do not suffer from conventional optical damage. The present status, remaining issues, and future perspectives of these so-called plasma-photonic devices for high-fi eld science and high-energydensity science will be discussed.View full abstractDownload PDF (554K) -
Yasuhiro KURAMITSU, Yoichi SAKAWA, Taichi MORITA, Toseo MORITAKA, Tak ...2013 Volume 41 Issue 1 Pages 20-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSKelvin-Helmholtz vortices and resultant turbulences are essential in many space and astrophysical phenomena, as in transport of solar wind to Earth’s magnetosphere,1） and triggered star formation in giant molecular clouds.2,3） However, while global images of astrophysical phenomena are obtained from their emissions, local observations of physical quantities are inaccessible. Antithetically, although local variables are obtained by direct measurements with spacecrafts, global structures are diffi cult to obtain in solar-terrestrial phenomena. An alternative way to investigate space and astrophysical phenomena is laboratory simulations; rapid growth of laser technologies allows us to model such phenomena in the laboratories. 4‒7） Here we report the experimental results of turbulent electric fi eld driven by Kelvin- Helmholtz instability associated with laser produced collisionless shock waves. Our results demonstrate that laboratory experiments are capable to identify the shock electric fi eld and related instability. This will provide us a complementary tool to investigate space and astrophysical phenomena.View full abstractDownload PDF (1409K) -
Norimasa OZAKI, Takayoshi SANO, Tomokazu SANO, Tomoaki KIMURA, Yos ...2013 Volume 41 Issue 1 Pages 25-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSLaser-driven dynamic compression has been used to study extreme matter states. High pressures and temperatures can be generated up to more than 104 GPa and 105 K, respectively, with using high-power laser. This approach, which has been developed as a strong driving force to obtain fusion power, now provides wider range of pressures, densities and temperatures. This review presents some basics and new topics in power-laser ultrahigh pressure research, and its future perspective.View full abstractDownload PDF (1315K) -
Hitoki YONEDA2013 Volume 41 Issue 1 Pages 33-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSIn this article, recent research works of warm dense matter are introduced. In the warm dense matte research, how to diagnose the condition is always discussed because there are several difficulties. Recently, there are many probe experiments with various probes produced by high power lasers. For example, the X-ray Thomson scattering is now strong tool for determining the electron temperature and density simultaneously. Beside it there are other potential methods to measure the parameters of the warm dense matter. They include the fast e-beam diffraction and photoelectron spectroscopy. Features of each probe measurement are briefly mentioned and the relation between unknown physics in warm dense matter and expected measured parameters from these new diagnostics are introduced.View full abstractDownload PDF (710K) -
Julien FUCHS, Bruno ALBERTAZZI, Jesús Álvarez RUIZ, Stefano ATZENI, A. ...2013 Volume 41 Issue 1 Pages 39-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSSignificant efforts are being conducted in various areas of high-energy-density (HED) science in Europe. In this frame, we will below review some recent results obtained in specific topics. In particular, we will outline recent experimental and theoretical results obtained in various fields as atomic physics, warm dense matter (matter with density above or equal solid, and temperatures above or equal to 1 eV), laserplasma interactions, the production of compact particle sources, magnetized plasmas, with relevance to varied applications like inertial confinement fusion (ICF), geophysics or astrophysics.View full abstractDownload PDF (665K) -
Farhat N. BEG, Booshan S. PARADKAR, Chris MCGUFFEY, Toshinori YABUUC ...2013 Volume 41 Issue 1 Pages 45-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSThe Fast Ignition (FI) Concept for Inertial Confinement Fusion (ICF) has the potential to provide a signifi cant advance in the technical attractiveness of Inertial Fusion Energy (IFE) reactors. FI is different from conventional “central hot spot” (CHS) target ignition due to separate compression and ignition phases. In this concept, laser (or heavy ion or Z pinch) drive pulses (10’s of ns) are used to assemble a dense fuel mass and a much shorter (~10 ps) high intensity pulse is used to ignite a small region of it. FI could signifi cantly reduce the driver energy (and cost) required for an IFE power plant. FI targets can burn with ~3X lower fuel density than CHS targets, resulting in (all other things being equal) lower required compression energy and relaxed drive symmetry/target smoothness requirements at a higher gain. Experiments in this area provide some of the most extreme High Energy Density (HED) conditions accessible. Here, we report results from experiments carried out using the OMEGA EP laser with ~ 1 kJ and 10 picosecond pulses. We used a gold cone attached to a copper wire to characterize the electrons generated by the laser by observing copper Kα and proton emission from the wire. Results show that the copper Kα yield increases with the laser energy, and proton emission is mainly due to three factors: i) the divergence of the fast electrons’ beam entering into the wire ii) the collisional scattering of fast electrons and iii) formation of a cloud of electrons around the wire due to the refl uxing of electrons from the far end of the wire.View full abstractDownload PDF (680K)
Laser Original
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Yosuke MISHIMA, Hideaki HABARA, Tomoyuki IWAWAKI, Kenshiro KIKUYAMA, T ...2013 Volume 41 Issue 1 Pages 49-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSWe studied the material dependence of electron acceleration with ultra-intense laser light at an intensity of 5 × 1019 W/cm2. Recent particle simulations have shown that the average energy of fast electrons stays lower than the prediction of ponderomotive scaling if intense laser light interacts directly with the target material. To control the fast electron energy spectra, we performed an experiment at the J-KAREN laser facility. The observed electron spectra show that the slope temperature for aluminum is 1.4 times higher than gold. The enhancement is strongly related to the average ioniation degree in the thin preplasma region in the PIC simulation result. The maximum proton energy reaches 10 MeV, and it shows the same values for Al, Cu and Au. The PIC simulations exhibit the values of the sheath fi eld at the target rear for Al, Cu, and Au, all of which are the same as the experiment.View full abstractDownload PDF (578K)
Regular Paper
Laser Original
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Jun AMAKO2013 Volume 41 Issue 1 Pages 54-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSWe report the design of diffractive beam splitters for dual-wavelength laser processing. They produce beam arrays for two different wavelengths in the way the arrays coincide at target points on a workpiece to process. The digitized surface profiles of the dual-wavelength splitters were designed using an iterative algorithm by considering the splitting performances, the material dispersion, and the wavelengths. For the chosen wavelengths of 1064 and 266 nm, as an example, we needed 32 phase levels and 42 pixels to obtain splitting effi ciencies of > 80% and splitting uniformities of > 0.90. The minimum pixel width was ~1% of the splitter period. The tolerances of the profi le errors were found to be ~1% of the designed depths. The shorter the wavelength is, the more sensitive the splitter performances are to the errors. Using achromatic splitters we can exploit the advantages of dualwavelength laser processing and attain a high throughput.View full abstractDownload PDF (886K) -
INOUE Tomoaki, Takayasu MOCHIZUKI, MIYAMOTO Shuji, Kazuya MASUDA, Sho ...2013 Volume 41 Issue 1 Pages 59-
Published: 2013
Released on J-STAGE: September 07, 2020
JOURNAL FREE ACCESSA ruthenium-coated cylindrical mirror was investigated to collect and focus the energy flux of 5- to 17-nm wavelength soft X-rays that are generated in a laser-produced xenon plasma. We found the mirror’s optimum position where the energy of transmitted and focused X-rays through the mirror was maximum, and determined the irradiation position where the spot diameter was minimum. The maximum intensity of the collected soft X-rays was 11 ± 1.5 J/m2 at the center of 1-mm in diameter focus spot. The energy density was improved by about 24 times compared with that without the mirror. These results suggest that a compact soft X-ray processing system can realized using laser plasma soft X-rays.View full abstractDownload PDF (915K)
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