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Your search keyword '"Ali, Safdar"' showing total 2 results
Start Over Author "Ali, Safdar" Topic ion traps Topic solar corona
2 results on '"Ali, Safdar"'

1. Intensity Ratio Measurements of EUV Spectra from Fe Ions Relevant to Solar Corona Diagnostics.

Author

Ali, Safdar, Erina Shimizu, Takashi Tsuda, Sakaue, Hiroyuki A., Daiji Kato, Izumi Murakami, Hirohisa Hara, Tetsuya Watanabe, and Nobuyuki Nakamura

Subjects
*ELECTRON beams, *ION traps, *RATIO measurement, *ULTRAVIOLET spectroscopy, *SPECTROMETERS, *ELECTRON density, *SOLAR corona
Abstract

We performed laboratory measurements to observe extreme ultraviolet (EUV) spectra of highly charged Fe ions using a compact electron beam ion trap. A high resolution flat-field grazing incidence spectrometer was employed to record spectra in the wavelength range of 160-230 Å. The intensity ratios were obtained as a function of electron density, which was experimentally determined from the spatial distribution of the ion cloud and the size of the electron beam. The results are compared with the SERTS 95 active region data and present model calculations. Our measured data points show rather good agreement with the observational data of SERTS 95 and calculated intensity ratios. [ABSTRACT FROM AUTHOR]

Published
2017
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2. Extreme ultraviolet spectra of S IX and S X relevant to solar coronal plasmas.

Author

Ali, Safdar, Kato, Hiroyuki, and Nakamura, Nobuyuki

Subjects
*ELECTRON beams, *ION traps, *ATOM trapping, *ULTRAVIOLET spectra, *PLASMA gases
Abstract

We present extreme ultraviolet laboratory spectra of highly charged S IX and S X measured using a compact electron beam ion trap. The data were recorded using a flat-field grazing incidence spectrometer in the wavelength range between 210 and 290 Å. The beam energy was tuned for three different values at 365, 410 and 465 eV while keeping electron beam current constant at 10 mA. By measuring the beam energy dependence, we identified several lines originating from S IX and S X ions with the support of collisional-radiative modeling. We compared them with the present calculations and transitions listed in the NIST data base and found in good agreement. [ABSTRACT FROM AUTHOR]

Published
2017
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