The assumption of the Maxwellian distribution is common in the analysis of astrophysical spectra. However, this assumption may be incorrect if the emitting plasma is heated dynamically e.g. by nanoflares. A possible signature of such dynamic heating in the solar corona would be the presence of non-Maxwellian distributions.
The κ-distributions, characterized by a high-energy tail, have been diagnosed in Si III SUMER spectra of the transition region (Dzifcakova & Kulinova 2011) and are also commonly observed in the solar wind (e.g. Maksimovic et al. 1997, Zouganelis 2008). Such distributions should result in an increase of the intensity of the coronal forbidden lines compared to the EUV ones (Dudík et al. 2014, A&A, submitted), an effect detectable by coordinated EIS and CoMP-S ground-based coronagraphic observations. This is the focus of this proposal.
However, to disentangle the effect of κ-distributions from the effects of the electron density and DEM, observations of additional EUV lines are needed for density and DEM diagnostics.
We propose this HOP to acquire unique joint observations by Hinode and CoMP‑S. As the target will be a limb active region, this will be a Target-of-Opportunity (ToO) HOP. The proposers will examine data from SDO and STEREO-A to determine, ahead of an observing plan, whether the observations should go ahead, and at which position angle on the limb. Given this point in the solar cycle, however, we expect that there will be a limb active region for much of the period.
If bad observing conditions are forecast at Lomnicky Peak, the observers there will inform the Hinode Chief Observers at least a day in advance that observations will not be required, in case there is time for Hinode to schedule other observations instead. |
|