Main Objective:
To obtain coincident data with the Hi-C sounding rocket flight in order to provide context for high resolution EUV data.
Scientific Justification:
Increases in spatial resolution provide an important avenue to understanding key physical processes by disentangling different structures and allowing them to be accurately characterized. Progress in this area has been evident in recent years in ground-based solar observations. Significant progress has also been made in X-ray (Yohkoh/SXT, NIXT, and Hinode/XRT) and UV (EIT, TRACE, and AIA, among others) instrumentation. However, even with the limited spatial resolution of these high-energy instruments (greater than 400 km), it was possible to discern that there was much unresolved spatial structure in the solar corona (Dere 2008, 2009; Warren et al. 2009; Tripathi et al. 2009).
The first flight of the High Resolution Coronal Imager (Hi–C) sounding rocket, on July 11, 2012, used a 4k x 4k detector to obtain more than 120 high-resolution images of the solar corona in order to explore the details present at smaller spatial scales than previously observed. The pixel scale was ~0.1 x 0.1 arcsec^2/pixel with an image cadence of approximately 2.5 seconds. The field of view for the full frame images was ~400 arcseconds. The images on the first flight were recorded through a 193Å filter with the same passband as the corresponding AIA channel. The mission launched on 2012 July 11 from White Sands Missile Range. Analysis of the retrieved data revealed significant finescale magnetic structure and dynamics throughout the images (Peter et al., 2013 A&A 556 104; Brooks et al., 2013 ApJ 772 L19; Morton & McLaughlin, 2014 ApJ 789 105; Winebarger et al., 2014, ApJ, 787 10, etc.; See https://hic.msfc.nasa.gov/publications.html for a full list of publications), with transverse spatial-scales on the order of those previously measured in the chromosphere.
A reflight (Hi-C 2) was attempted on 2016 July 27, but did not successfully retrieve science data due to a malfunctioning camera shutter. Hi-C is scheduled for another reflight attempt (Hi-C 2.1) on 2018 May 29. Compared to the first flight, Hi-C 2.1 uses new detectors, with lower read noise. As a tradeoff for markedly improved read noise, the reflight will have a smaller field of view (~260 arcsec) due to a reduced detector size (4k x 4k to 2k x 2k). The bandpass filter for the observations will also be changed from FeXII 193 Å to FeIX 173 Å. We request observations with Hinode with improved pointing coordination. We propose to obtain contextual coronal images from XRT, plasma diagnostics from EIS, and high-resolution magnetic field data from SOT. These data will provide comparisons between the low-temperature coronal data from Hi-C 2.1, particular at active region footpoint regions, with the surface and the outer atmosphere. Combined with IRIS data, this will give a broad picture of the nature of smallscale reconnection and dynamics or magnetoacoustic oscillations. |
|