discussion of atomic data for O IV and Si OV (trac #372)

reported by: @CloudyLex

see especially the appendix. We need to update this once the dust settles.

Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS 
Polito, V., Del Zanna, G., Dud\ik, J., Mason, H. E., Giunta, A., & Reeves, K. K.
2016, \aap, 594, A64

ABSTRACT: The intensity of the O iv 2s2 2p 2P-2s2p24P and S iv 3 s2 3p 2P-3s 
3p24 P intercombination lines around 1400 Å observed with the Interface Region 
Imaging Spectrograph (IRIS) provide a useful tool to diagnose the electron 
number density (Ne) in the solar transition region plasma. We measure the 
electron number density in a variety of solar features observed by IRIS, including 
an active region (AR) loop, plage and brightening, and the ribbon of the 22-June-
2015 M 6.5 class flare. By using the emissivity ratios of O iv and S iv lines, we find 
that our observations are consistent with the emitting plasma being near 
isothermal (logT[K] ? 5) and iso-density (Ne ? 1010.6 cm-3) in the AR loop. 
Moreover, high electron number densities (Ne ? 1013 cm-3) are obtained during 
the impulsive phase of the flare by using the S iv line ratio. We note that the S iv 
lines provide a higher range of density sensitivity than the O iv lines. Finally, we 
investigate the effects of high densities (Ne ? 1011 cm-3) on the ionization 
balance. In particular, the fractional ion abundances are found to be shifted 
towards lower temperatures for high densities compared to the low density case. 
We also explored the effects of a non-Maxwellian electron distribution on our 
diagnostic method.  The movie associated to Fig. 3 is available at 
http://www.aanda.org

KEYWORDS: Sun: transition region, Sun: UV radiation, techniques: spectroscopic, atomic data
NOTE: 

REMOTE URL : http://dx.doi.org/10.1051/0004-6361/201628965
REMOTE URL : http://arxiv.org/abs/1607.05072
REMOTE URL : http://adsabs.harvard.edu/abs/2016A%26A...594A..64P
ADS URL : http://adsabs.harvard.edu/abs/2016A%26A...594A..64P

Migrated from https://www.nublado.org/ticket/372

{
    "status": "new",
    "changetime": "2019-02-04T13:02:49Z",
    "_ts": "1549285369825011",
    "description": "see especially the appendix.  We need to update this once the dust settles.\n{{{\nDensity diagnostics derived from the O iv and S iv intercombination lines observed by IRIS \nPolito, V., Del Zanna, G., Dud\\ik, J., Mason, H. E., Giunta, A., & Reeves, K. K.\n2016, \\aap, 594, A64\n\nABSTRACT: The intensity of the O iv 2s2 2p 2P-2s2p24P and S iv 3 s2 3p 2P-3s \n3p24 P intercombination lines around 1400 \u00c5 observed with the Interface Region \nImaging Spectrograph (IRIS) provide a useful tool to diagnose the electron \nnumber density (Ne) in the solar transition region plasma. We measure the \nelectron number density in a variety of solar features observed by IRIS, including \nan active region (AR) loop, plage and brightening, and the ribbon of the 22-June-\n2015 M 6.5 class flare. By using the emissivity ratios of O iv and S iv lines, we find \nthat our observations are consistent with the emitting plasma being near \nisothermal (logT[K] ? 5) and iso-density (Ne ? 1010.6 cm-3) in the AR loop. \nMoreover, high electron number densities (Ne ? 1013 cm-3) are obtained during \nthe impulsive phase of the flare by using the S iv line ratio. We note that the S iv \nlines provide a higher range of density sensitivity than the O iv lines. Finally, we \ninvestigate the effects of high densities (Ne ? 1011 cm-3) on the ionization \nbalance. In particular, the fractional ion abundances are found to be shifted \ntowards lower temperatures for high densities compared to the low density case. \nWe also explored the effects of a non-Maxwellian electron distribution on our \ndiagnostic method.  The movie associated to Fig. 3 is available at \nhttp://www.aanda.org\n\n\nKEYWORDS: Sun: transition region, Sun: UV radiation, techniques: spectroscopic, atomic data\nNOTE: \n\nREMOTE URL : http://dx.doi.org/10.1051/0004-6361/201628965\nREMOTE URL : http://arxiv.org/abs/1607.05072\nREMOTE URL : http://adsabs.harvard.edu/abs/2016A%26A...594A..64P\nADS URL : http://adsabs.harvard.edu/abs/2016A%26A...594A..64P\n\n}}}",
    "reporter": "gary",
    "cc": "",
    "resolution": "",
    "time": "2016-10-24T17:34:28Z",
    "component": "atomic/molecular data base",
    "summary": "discussion of atomic data for O IV and Si OV",
    "priority": "good to do",
    "keywords": "",
    "version": "trunk",
    "milestone": "no milestone",
    "owner": "nobody",
    "type": "enhancement"
}

cloudy-astrophysics / bug-tracker-migration-test

discussion of atomic data for O IV and Si OV (trac #372) #374