HOP 0338

proposer

name :

Utz,Kuckein, Denker,Balthasar,Verma, Gonzalez, Ichimoto,Goemoery, Koza, Bellot-Rubio,Orozco-Suarez, van Doorsselaere, Magyar, Vargas Dominguez, Guo, Wedemeyer-Boehm, Kato,Temmer,Hofmeister,Camos Rozo,Williams

e-mail :

Dominik.Utz[at]uni-graz.at,ckuckein[at]aip.de, cdenker[at]aip.de, hbalthasar[at]aip.de, mverma[at]aip.de, smanrique[at]aip.de, ichimoto[at]kwasan.kyoto-u.ac.jp, gomory[at]ta3.sk, koza[at]ta3.sk, lbellot[at]iaa.es, orozco[at]iaa.es, tom.vandoorsselaere[at]kuleuven.be, norbert.magyar[at]kuleuven.be, svargasd[at]unal.edu.co, guoyang[at]nju.edu.cn, sven.wedemeyer[at]astro.uio.no, yoshiaki.kato[at]astro.uio.no, manuela.temmer[at]uni-graz.at, stefan.hofmeister[at]uni-graz.at, jose.campos-rozo[at]uni-graz.at, david.williams[at]esa.int

abstract of observational proposal

Main Objective:
Investigating the magnetic coupling from the photosphere to the higher layers by tracking the evolution of MBPs and the created fibril and mottle structures.

Scientific Justification:
This is an accepted observational proposal and campaign for the ground-based GREGOR telescope with IRIS and VTT already going to support the campaign. Hinode support would be crucial for a further extension of the observations to the higher solar atmosphere. Below we will give a shortened version of the justification from the original GREGOR proposal. If wished, the whole document could be e-mailed.

The main objective of the proposal is to understand the coupling between the photosphere and the lower chromosphere of the quiet Sun by investigating the dynamics of small-scale magnetic fields in the photosphere which leads to the creation of fibrils and mottles in the lower chromosphere. As a secondary or extended goal we wish to relate these observed changes in the lower atmosphere to changes in the higher atmosphere, e.g. to the coronal magnetic field topology as seen by coronal holes or closed magnetic structures (EIS and XRT support). This means that we need to understand and investigate:

The dynamics of small-scale solar magnetic fields: In order to investigate the dynamics of the magnetic flux elements we will track the path of MBPs in the photosphere. For this purpose we need G-band images of the photosphere (GREGOR). These images will be analysed with local correlation tracking methods (LCT; e.g., Vargas Domnguez et al., 2008) to display the apparent plasma motions. Afterwards we can relate these LCT results to the direct tracking results of MBPs enabling us to answer the question if and how MBPs are moved, perturbed, and buffeted by the surrounding convective flows.

The reaction of the magnetic flux tube on the granulation Dynamics (GREGOR/GRIS and Hinode/SOT/SP): Due to the dynamics of the magnetic flux tube in the photosphere, the plasma parameters of the magnetic field concentration will change. Of strong interest are the magnetic field strength, the line of sight (LOS) velocity, and the temperature; as well as the stratification of these parameters with height. The scientific question to be answered is how the magnetic field seen as flux tube/MBP reacts on the convective dynamics in the photosphere.
The creation of fibrils/mottles (GREGOR/GFPI, VTT/TESIS, IRIS & Hinode/EIS & XRT): We believe that visible upflows in magnetic field concentrations willlead later on to the development of dark fibrils and mottles seen on the solar disc in H-alpha line-scan data . Thus relating the gained information from the previous task to observations in the H-alpha line wing will enable us to get a deeper understanding of the involved physical processes (e.g. VTT/TESIS). For the higher atmosphere additional investigations and information can be gained by IRIS, Hinode/EIS & XRT.

request to EIS

We would have created a line list (Nr. 284: Utz_quiet) containing the 3 necessary lines as well as the strongest recommended lines for density estimations; Fe X (pair), Fe XI, Fe XII (pair), Fe XIII (tripple), Fe XIV (tripple), Ca XVII, He II;

We also created a raster/study: (Nr. 538: Utz_quiet)
Scanning, 1 arcsec slits, with a height of 160 pixel, the standard width of 32 pixel, a FOV of ~ 20 arcsec by 160 arcsec (10 scan positions always skipping one position in between). DCPM loseless compression and an exposure time of 1 Minute per scan position giving a cadence of 11 min 55 sec and a data rate of 6.7169 kbit/s.

other participating instruments

IRIS Requests:
The proposal was sent to IRIS POC and the proposers already got the confirmation of IRIS support in the period from 20.9.2017 to 30.9.2017 on each day between 11:00 UT to 14:00 UT

OBS: 3600258038 | Medium sparse 16-step raster 15x60 16s Deep x 8 FUV spectrally rebi | 150.11 | 97.23 | 0.4 | 9.4+/-0.1 | 150+/-0 | 37.5+/-0.0 | 37.5+/-0.0 | 37.5+/-0.0 | 37.5+/-0.0

During second half of campaign, possibly use
OBS: 3600258029 | Medium sparse 8-step raster 7x60 8s Deep x 8 FUV spectrally rebinne | 74,81 | 48,61 | 0,4 | 9,4+/-0,1 | 74,8+/-0,0 | 37,4+/-0,1 | 37,4+/-0,1 | 37,4+/-0,1 | 37,4+/-0,1

Additional instrument coordination:
This is a GREGOR ground-based telescope proposal with the additional support of VTT;

remarks

Dates: 1) starting date 20.9.2017 (The ground based campaign will already start at the 18.9, but we expect that we will need the first time for instrumental set up and learning how to handle the telescope adequately; also IRIS support will start from the 20.9.2017 onwards); ending date 30.9.2017 (The campaign will finish on this day); 2) If possible we would ask for the full support during these days, as the ground-based observations are depending on the seeing conditions, which are out of our control. In case of acuqiring outstanding data early in the campaign, the support could be finished earlier. 3) Except of the given reasoning under 2nd, nothing special is requested;

Time window: From 9:00 UT to 13:00 UT; Reasoning: generally the seeing conditions on site of GREGOR are better in the morning hours. However, due to non availability of IRIS in the early hours (supporting SST), our campaign gets IRIS support from 11:00 UT to 14:00 UT. Thus the best trade off between seeing and combined instrumental support would be, to start early with Hinode, so as to catch the good seeing window of opportunity, but then, also to prolong into the IRIS period, to have in addition all instruments working together.

Target(s) of interest: The target of interest should be quiet Sun slightly out of the disc centre to avoid projecting the fibrils/mottles directly on top of the MBPs. For alignment purposes a small pore in one of the corners of the FOV would be preferred.

Previous HOP information:
Up to now the proposer has not made use of HOPs but used extensively existing Hinode data for his publications:
Utz et al. 2009: The size distribution of magnetic bright points derived from Hinode/SOT observations
Utz et al. 2010: Dynamics of isolated magnetic bright points derived from Hinode/SOT G-band observations
Utz et al. 2013: Magnetic field strength distribution of magnetic bright points inferred from filtergrams and spectro-polarimetric data
Utz et al. 2013: Variations of Magnetic Bright Point Properties with Longitude and Latitude as Observed by Hinode/SOT G-band Data and Utz et al. 2016: Long-term trends of magnetic bright points. I. Number of magnetic bright points at disc centre

Additional Remarks:
If required the full GREGOR proposal could be sent via E-Mail.
Any remarks or suggestions to the proposal would be also very welcome.