Polarization measurement of dielectronic recombination transitions in highly charged krypton ions
Chintan Shah, Holger Jörg, Sven Bernitt, Stepan Dobrodey, René Steinbrügge, Christian Beilmann, Pedro Amaro, Zhimin Hu, Sebastian Weber, Stephan Fritzsche, Andr… 展开作者
Chintan Shah, Holger Jörg, Sven Bernitt, Stepan Dobrodey, René Steinbrügge, Christian Beilmann, Pedro Amaro, Zhimin Hu, Sebastian Weber, Stephan Fritzsche, Andrey Surzhykov, José R. Crespo López-Urrutia, Stanislav Tashenov
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11 pages, 4 figures (Note that the Eqs. (5) and (10) of the original paper are corrected in Physical Review A 94, 029905(E) (2016). doi:10.1103/PhysRevA.94.029905)
We report linear polarization measurements of x rays emitted due to dielectronic recombination into highly charged krypton ions. The ions in the He-like through O-like charge states were populated in an electron beam ion trap with the electron beam energy adjusted to recombination resonances in order to produce $Kα$ x rays. The x rays were detected with a newly developed Compton polarimeter using a beryllium scattering target and 12 silicon x-ray detector diodes sampling the azimuthal distribution of the scattered x rays. The extracted degrees of linear polarization of several dielectronic recombination transitions agree with results of relativistic distorted--wave calculations. We also demonstrate a high sensitivity of the polarization to the Breit interaction, which is remarkable for a medium-$Z$ element like krypton. The experimental results can be used for polarization diagnostics of hot astrophysical and laboratory fusion plasmas.
Dielectronic recombination data for astrophysical applications: Plasma rate-coefficients for Fe^q+ (q=7-10, 13-22) and Ni^25+ ions from storage-ring experiments
Fe$^{\bf{15+}}$ dielectronic recombination and the effects of configuration interaction between resonances with different captured electron principal quantum number
Suppression of Dielectronic Recombination Due to Finite Density Effects II: Analytical Refinement and Application to Density-dependent Ionization Balances and AGN Broad-line Emission
A free electron can form a bound state with an atomic center $A$ upon photo emission (radiative recombination). In the presence of a neighboring atom $B$, such a bound state can, under certain conditions, be also formed via resonant transfer of energy to $B$, with its subsequent relaxation through radiative decay (two-center dielectronic recombination). This two-center process is very efficient in the 'static' case where $A$ and $B$ form a weakly bound system, dominating over single-center radiative recombination up to internuclear distances as large as several nanometers. Here we study its dy…
Theoretical and experimental resonance strengths for KLL dielectronic recombination (DR) into He-, Li-, Be-, and B-like mercury ions are presented, based on state-resolved DR x-ray spectra recorded at the Heidelberg electron beam ion trap. The DR resonance strengths were experimentally extracted by normalizing them to simultaneously recorded radiative recombination signals. The results are compared to state-of-the-art atomic calculations that include relativistic electron-electron correlation and configuration mixing effects. Combining the present data with other existing ones, we derive an im…
我们提出了一个理论研究的双电子复合(DR)的Ar类离子,揭示了新的光的速率系数的行为在低温下,这些离子形成的光电离等离子体。我们提供的总的和部分麦克斯韦平均DR率系数从K II -锌XIII离子的初始基态的结果。预计这些新的结果将提高类Ar M壳层离子电离平衡的准确性,并为天体物理相关X射线吸收特征的详细建模铺平道路。我们利用AUTOSTRUCTURE计算程序获得了目标离子的准确的核心激发阈值,并在独立过程、孤立共振、扭曲波(IPIRDW)近似下对DR截面进行了多组态Breit-Pauli(MCBP)计算。我们的研究结果调解完全没有直接DR计算某些类Ar离子和现有的经验速率公式的可靠性,往往推断出在此等电子序列的重整化数据的问题。
We investigated experimentally and theoretically dielectronic recombination (DR) populating doubly excited configurations $3l3l'$ (LMM) in Fe XVII, the strongest channel for soft X-ray line formation in this ubiquitous species. We used two different electron beam ion traps and two complementary measurement schemes for preparing the Fe XVII samples and evaluating their purity, observing negligible contamination effects. This allowed us to diagnose the electron density in both EBITs. We compared our experimental resonant energies and strengths with those of previous independent work at a storage…
The experimental thermonuclear reactor, ITER, is currently being constructed in Cadarache, France. The reactor vessel will be constructred with a beryllium coated wall, and a tungsten coated divertor. As a plasma-facing component, the divertor will be under conditions of extreme temperature, resulting in the sputtering of tungsten impurities into the main body plasma. Modelling and understanding the potential cooling effects of these impurities requires detailed collisional-radiative modelling. These models require a wealth of atomic data for the various atomic species in the plasma. In partic…
Tungsten is an important element for magnetically confined fusion plasmas but has the potential to cool, or even quench the plasma due to it being an efficient radiator. Total and level-resolved dielectronic recombination (DR) rate coefficients, for all ionization stages, are essential to model tungsten. We describe a set calculations performed using the distorted wave code AUTOSTRUCTURE for the tungsten ions W$^{37+}$ to W$^{28+}$. We demonstrate the importance of relativistic configuration mixing in such calculations. In particular, we show that the partial DR rate coefficients calculated in…
Motivated by possible atomic origins of the unidentified emission line detected at 3.55 keV to 3.57 keV in a stacked spectrum of galaxy clusters (Bulbul et al. 2014), an electron beam ion trap (EBIT) was used to investigate the resonant dielectronic recombination (DR) process in highly-charged argon ions as a possible contributor to the emission feature. The He-like Ar DR-induced transition 1s$^2$2l - 1s2l3l$^\prime$ was suggested to produce a 3.62 keV photon (Bulbul et al. 2014) near the unidentified line at 3.57 keV and was the starting point of our investigation. The collisional-radiative m…
Rate coefficients for dielectronic recombination of N-like Ne
GSI Helmholtzzentrum für Schwerionenforschung GmbH(吉西亥尔姆霍兹重离子研究中心有限公司);Helmholtz-Institut Jena(耶拿亥尔姆霍兹研究所);Institut für Kernphysik, Goethe Universität(歌德大学核物理研究所);Institut für Kernphysik, Universität zu Köln(科隆大学核物理研究所);I. Physikalisches Institut, Justus-Liebig-Universität(吉森大学第一物理研究所);Helmholtz Forschungsakedemie Hessen für FAIR (HFHF)(黑森亥尔姆霍兹FAIR研究学院);Physics Department, Auburn University(奥本大学物理系)
Storage ring measurement of the C IV recombination rate coefficient
在德国海德堡的Max-Planck-Institut fuer Kernphysik的重离子储存环TSR上,用高能量分辨率测量了这种类锂离子的2s-2 p Delta n=0激发的低能C-IV双电子复合(DR)速率系数。详细讨论了该离子复合产生的高里德堡态的实验过程,特别是实验探测几率。从实验数据的麦克斯韦等离子体速率系数与15%的系统不确定性和参数化准备使用等离子体建模代码。我们的实验结果,特别是基准的等离子体速率系数低于10000 K DR主要通过C III(1 s2 2 p 4l)中间状态和现有的理论不同的数量级发生。此外,我们发现总的双电子和辐射C IV复合可以由我们的DR速率系数和Pequignot等人的RR速率系数的非相干和(1991,Astron. Astrophys.,251,680)。
The Abundances of Light Neutron-Capture Elements in Planetary Nebulae III. The Impact of New Atomic Data on Nebular Selenium and Krypton Abundance Determinations
High precision spectroscopy of the low-lying dielectronic resonances in fluorine-like nickel ions were determined by employing the merged electron-ion beam at the heavy-ion storage ring CSRm. The measured dielectronic resonances are identified by comparing with the most recent relativistic calculation utilizing the FAC code. The first resonance at about 86 meV due to the dielectronic recombination via (2s2p6[2S1/2]6s)J=1 intermediate state was recognized. The experimental determination of the resonance position at 86 meV reaches an uncertainty of 4 meV, which allows precise determination of th…