Downloads provided by UsageCounts
Abstract We analyze the coronal elemental abundances during a small flare using Hinode/EIS observations. Compared to the preflare elemental abundances, we observed a strong increase in coronal abundance of Ca xiv 193.84 Å, an emission line with low first ionization potential (FIP < 10 eV), as quantified by the ratio Ca/Ar during the flare. This is in contrast to the unchanged abundance ratio observed using Si x 258.38 Å/S x 264.23 Å. We propose two different mechanisms to explain the different composition results. First, the small flare-induced heating could have ionized S, but not the noble gas Ar, so that the flare-driven Alfvén waves brought up Si, S, and Ca in tandem via the ponderomotive force which acts on ions. Second, the location of the flare in strong magnetic fields between two sunspots may suggest fractionation occurred in the low chromosphere, where the background gas is neutral H. In this region, high-FIP S could behave more like a low-FIP than a high-FIP element. The physical interpretations proposed generate new insights into the evolution of plasma abundances in the solar atmosphere during flaring, and suggests that current models must be updated to reflect dynamic rather than just static scenarios.
The Sun, Solar physics, 1496, 1474, 1693, Sun: abundances - Sun: corona - Sun: magnetic fields, 1476, FOS: Physical sciences, 530, 520, [SDU] Sciences of the Universe [physics], Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], Solar flares, Solar abundances, Solar and Stellar Astrophysics (astro-ph.SR)
The Sun, Solar physics, 1496, 1474, 1693, Sun: abundances - Sun: corona - Sun: magnetic fields, 1476, FOS: Physical sciences, 530, 520, [SDU] Sciences of the Universe [physics], Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], Solar flares, Solar abundances, Solar and Stellar Astrophysics (astro-ph.SR)
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 21 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
| views | 3 | |
| downloads | 5 |

Views provided by UsageCounts
Downloads provided by UsageCounts