MUTA calculations of a laser-produced Mg hollow atom spectrum

Abstract

A study is made of the spectra produced from a short-wavelength long-pulse (nanosecond) laser incident on a Mg plasma. A very complex experimental spectrum is analyzed in detail by comparison with large-scale atomic kinetics calculations using the recently developed mixed-UTA (MUTA) model. We find that the experimental spectrum appears to contain lines from many inner-shell transitions from ions ranging from neutral Mg to Li-like Mg. Lines from transitions such as 1s-3l, 1s-4l, and from hollow atoms (where in this context hollow atoms refer to ions with an empty 1s shell) are observed. The inclusion of very small fractions of hot electrons is demonstrated to make significant differences to the spectra. Although it is found that the calculations do not match perfectly the experimental spectra, reasonable agreement between the experiment and the theory can be obtained if temperature and density gradients are assumed present in the experimental conditions.

Diagnostics of warm dense matter by high-resolution X-ray spectroscopy of hollow ions

“…Therefore, until now, hollow ion spectra were observed practically only in the femtosecond laser-produced plasma in the cases when laser did not produce preplasma due to the rather low laser intensity (Gauthier et al, 1995) or due to very high (above 10 9 ) laser contrast (see, for example, Faenov et al, 1997;1999;Urnov et al, 1998;Rosmej et al, 2000;Colgan et al, 2008;Skobelev et al, 2012). For longer laser pulse, hollow ion spectra have been observed where short wavelength eximer XeCl-laser or 2w of Nd laser were used (Abdallah et al, 2000;Colgan et al, 2008a;Colgan 2010).…”

Analysis of Mg spectral features produced by irradiations of laser pulses with different contrast and pulse durations

“…Results are given for the 1s 2 decay channel and the sum of the 1s 2 , 1s2s, and 1s2p decay channels. Those results are given in columns labelled as '+ 1s2l , while results only including the 1s 2 7.8485 8.20 [12] 2.74 [12] 4.07 [13] 1489.3 150.3 6.32 [11] 5.67 [12] 5.95[−1] 7.73 [1] Table 5. Wavelengths (λ in Å), radiative rates (gA r in s −1 ), autoionization rates (gA a in s −1 ), Auger energies (E s in eV), intensity factors (Q d in s −1 ) and effective emission rate coefficients (C eff in 10 −15 cm 3 s −1 ) (T e = 600 eV) for the 1s 2 3l3l -1s3l3l 3l Li-like Mg transitions calculated using the COWAN code.…”

“…Laser-produced plasmas have been shown to be excellent sources for satellite structure studies [12][13][14][15][16][17][18][19]. The high electron densities provide conditions for typically insignificant satellite lines to be prominent enough for detailed examination.…”

“…A 375-D 353 8.4368 8.12[12] 6.00[12] 1.367 4.40[−1] 1.32[13] 1.52[−14] A 377-D 355 8.4347 7.43[12] 7.62[12] 1.367 3.73[−1] 1.99[13] 2.30[−14] A 379-D 357 8.4320 1.20[13] 9.34[12] 1.367 5.63[−1] 4.73[13] 5.45[−14] B 133-S 111 8.4203 6.69[12] 3.69[13] 1.369 1.46[−1] 1.62[13] 1.86[−14] 2l5l -1s5l transitions A 177-D 155 8.4171 7.56[12] 5.04[12] 1.407 5.07[−1] 1.79[13] 1.93[−14] I 377-D 155 8.4183 1.45[12] 1.70[13] 1.407 7.80[−2] 9.27[12] 1.00[−14] A 379-D 357 8.4257 1.22[13] 4.41[12] 1.406 7.35[−1] 2.91[13] 3.15[−14] B 133-S 111 8.4209 7.25[12] 1.84[13] 1.406 2.63[−1] 1.45[13] 1.57[−14]…”