[en] An atomic modeling based on the plasma microfield is considered. In the atomic modeling, it is considered that an ion in plasma is immersed in a uniform electric field due to the field values averaged over the other ions in the plasma. Using the modeling, we can compute the average ionization degree of hydrogenic plasmas without any ad hoc parameters to cut of the number of bound states. (author)

[en] A time resolved laser induced breakdown spectroscopy technique (LIBS) was used for the investigation of emission signal enhancement on double-pulse LIBS. Two Q-switched Nd:YAG lasers at 1064 nm wavelength have been employed to generate laser-induced plasma on aluminium-based alloys. The plasma emission signals were recorded by spectrometer with ICCD detector. Spectral response calibration was performed by using deuterium and tungsten halogen lamps. Time evolution of the plasma temperature and electron density was investigated in SP and DP experiments. Based on the investigation of plasma parameters, the enhancements of emission line intensities were investigated, and the mechanisms of it were discussed. (author)

[en] Multiple ionization dynamics of rare gas dimers by slow highly charged ions is investigated with the three-center Coulombic over-barrier model. Quasi-molecule formation of an electron at the distant atomic site from the projectile is shown sensitive to partial screening of ion-core charged at the near atomic site due to electrons already forming quasi-molecules. It is found that the screening effect suppresses simultaneous chained electron removal from both sites and hence enhances charge-asymmetric ion pair formation. The ion pair distribution measured in Ar"9"+ + Ar_2 collisions is well reproduced by taking a screening factor of s = 0.4 in the model. (author)

[en] We present spectra of highly charged tungsten ions in the extreme ultra-violet (EUV) by using electron beam ion traps. The electron energy dependence of spectra is investigated of electron energies from 490 to 1440 eV. Previously unreported lines are presented in the EUV range, and some of them are identified by comparing the wavelengths with theoretical calculations. (author)

[en] Laser-induced breakdown spectroscopy (LIBS) has been applied to the analysis of heavy metals in liquid sample. A new approach was presented to improve the detection limit and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions, respectively. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to obtained LOD of 0.07 ppm for Cr element in solutions. (author)

[en] Hydrogen-like nitrogen plasma is expected as one of light sources to generate extreme ultraviolet (EUV) light. A hydrogen-like nitrogen ion emits a photon at 13.4 nm with an optically allowed transition from n=3 to n=2, where n stands for a principal quantum number. We focus on the properties of the population inversion between n=3 and n=2, and estimate the lasing potential by numerical simulation. In our previous study, higher gain-length products GL are obtained and desired plasma conditions are found. In this paper, our study up to now is surveyed and the effect of photo processes due to amplified EUV light during the propagation in plasma is considered. The present status of this study will be also briefly reported. (author)

[en] Absolute Kα line spectroscopy is proposed to study laser-plasma interactions taking place in the core-guided fast ignition targets. A transmission-type spectrometer was developed, and its absolute sensitivity was measured with laser-generated x-rays and radioisotopes, showing good agreement with theoretical predictions. The absolute yield of Au Kα line was measured in the fast ignition experimental campaign performed at ILE Osaka U.. Assuming a single Maxwellian electron spectrum and one-way travel of hot electrons through the cone, energy transfer efficiency of incident LFEX laser to hot electrons was derived. (author)

[en] As one of the activities of JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics (NSFC: No.11261140328), Japan-China Joint Seminar on Atomic and Molecular Processes in Plasma was held on July 30 - August 4, 2012, in Lanzhou, China. The total number of the officially registered participants was 37, in which 14 from Japan, 21 from China, 1 from Germany, and 1 from Ireland. This seminar is the extension of the last three seminars that were held on March 6-11, 2004 in Lanzhou, China, on October 6-12, 2007 in Dunhuang, China, and on October 26-31, 2009 in Xi'an, China. In the nuclear fusion plasma, there are quite a variety of atomic processes such as ionization, excitation, di-electronic recombination, collisional electron transfer, cascade radiation, and cascade Auger decay over the wide range of plasma temperature. The knowledge of those processes is indispensable for the evaluation and improvement of the plasma properties. Especially, in these years, the property of tungsten ions has become a subject of urgent investigations since tungsten has been considered as one of the plasma facing wall materials. Because of the diversity of the subject, it is desirable to investigate them by international collaboration groups. The present seminar may contribute to realize the above stated aim; especially it has given an opportunity for the collaborative workers to illustrate their achievements. The present seminar summarizes the collaborative researches for the last decade and proposes the issues for the future prospect. This issue is the collection of 19 papers presented at the entitled meeting. All the 19 of the presented papers are indexed individually. (J.P.N.)

[en] We present recent results at the Tokyo electron beam ion trap (Tokyo-EBIT) for the angular distribution of x-rays emitted in dielectronic recombination processes. Since the observation angle of the Tokyo-EBIT is restricted to 90deg with respect to the electron beam, it is impossible to obtain the angular distribution directly. We have thus combined the differential x-ray measurements at 90deg and the integral measurements through ion-abundance to obtain the asymmetric parameter. By comparing with the theoretical result by Fritzsche et al. [Phys. Rev. Lett. 103, 113001 (2009], anomalously strong effects of the Breit interaction on the angular distribution has been clearly demonstrated. (author)

[en] To study doubly excited states of simple molecules, total and total ionic generalized oscillator strength distributions (GOSDs) and ionization efficiencies of molecular hydrogen (H_2), ammonia (NH_3), and methane (CH_4) were investigated using scattered electron-ion coincidence technique under magnitude of momentum transfer is not zero conditions. Absolute GOSDs obtained by application of a mixed gas method were very similar to previous OOSDs in shape. From ionization efficiencies obtained, it was clear that optically forbidden doubly excited states exist near 28 and 35 eV for H_2, near 30 eV for NH_3, and near 35 eV for CH_4. (author)