Subject: eis_co

From: Peter Gomory <[email-masked]>
Date: Mon, 26 Mar 2007 10:41:34 +0000 (UTC)

Dear EIS planners, 

we have already applied for the observing time in a frame of the joint 
observing campaign of the SOHO/SUMER and HINODE/EIS spectrometers
following suggestion of the SUMER PI Werner Curdt. 
This program was included to the SOHO+HINODE April 2007 campaign 
(program 25) scheduled for week 15. 

In this e-mail we would like to describe scientific objective of our 
proposal and also observational details for the EIS and SUMER 
spectrometers in order to specify all detail for the EIS instrument.

The detailed scientific justification of our observing program and the 
description of the SUMER and EIS observing details can be found at 
http://www.mps.mpg.de/homes/curdt/hinode/HINODE_cases.html
(observing program nr. 25). But some basics are included below as well.

Attached you will also find the SolarSoft/EIS produced definition of 
the EIS study (eis_program.def). We would like to ask you if you can 
perform basic tests of our study definition in order to confirm 
its suitability for the EIS measurements and to let us know about
the result.  

Scientific objective:
---------------------
Title: Energy transport and dynamics in/above the 
       solar network and coronal heating mechanisms

Upper parts of the solar atmosphere (i.e. chromosphere, 
transition region and corona) are planned to be 
investigated in order to identify the most probable  
physical mechanism responsible for the heating of the 
solar corona localized particularly in/above chromospheric 
network. 

At present, two main groups of the physical mechanisms 
are proposed to understand coronal heating problem: 
dissipation of magneto-acoustic waves excited in the 
photosphere and small-scale magnetic reconnection in 
the corona. Although these two groups of mechanisms 
are based on different physics, both suggest presence 
of the propagating waves in the upper solar atmosphere 
(e.g. Hansteen et al., 1996, ASP Conf.Ser. 111,116). 
Difference is situated in the opposite direction of the 
wave propagation (e.g. Wikstol et al., 1997, ApJ 483, 972). 
Determination of the dominant mechanism can be therefore 
based on analysis of the wave modulation of the spectral 
lines emissions.

Our latest results indicate presence of the downward 
propagating waves in/above chromospheric network and thus 
preferring magnetic reconnection as the dominant heating 
mechanism (Gomory et al., 2006,  A&A 448, 1169). On the 
other hand, findings of  other authors (e.g. Curdt et al., 
1999, ESA SP-448, 177; Marsh et al., 2003, A&A 404, L37) 
show evidence of propagating intensity oscillations 
spreading out from the photosphere to the corona and 
therefore preferring the alternative heating mechanism. 

To clarify these findings we propose the following 
simultaneous measurements of the HINODE/EIS and SOHO/SUMER 
spectrometers:

EIS observational details:
-------------------------- 
- 2D images of the limited field-of-view 
- slot: 40" 
- FOV: 40x200"
- spectral lines: He II 256.32 A - chromosphere (4.8)
                  Si VII 275.35 A - transition region (5.7) 
                  Fe XII 195.12 A - corona (6.11)
                  Ca XVII 192.82 A - corona (6.7)
- pointing: centered at the SUMER slit position  
- cadence: ~12 sec.
- provided information: line emission 
- total run duration: minimum: ~3.5 hours
                      optimum: ~7.0 hours (two repetitions of the 
                                           proposed eis_program.def
                                           study)
  (measurements repeated for several days in order to acquire 
   sufficiently large material also for a statistical analysis 
   of more network areas)

SUMER observational details: 
----------------------------
- time series of the line profiles  
- spectral lines: C II 1036.34 A and 1037.018 A - chromosphere 
                  O VI 1037.613 A - transition region 
- fixed 1D slit position near disk center 
- slit: 1x120 arcsec 
- no rotation compensation.
- provided information: spectral images 75x120 pixels 

The acquired SUMER and EIS data are planned to be used for 
study of possible waves in the upper solar atmosphere and 
for determination of direction of their propagation. We 
will employ improved cross-correlation algorithm (e.g. 
Gomory et al., 2004, ESA SP-575, 400), wavelet analysis 
(Torrence & Compo, 1998, Bull. Amer. Meteor. Soc. 79, 61) 
and phase difference analysis (e.g. Bloomfield et al., 2004, 
ApJ 617, 623) of the SUMER 1D and EIS 2D line intensities 
(and 1D SUMER Doppler shifts) of all selected spectral lines. 
This approach has been used already by our group for CDS data 
(Gomory et al., 2006, A&A 448, 1169).

We expect that merging of the 1D SOHO/SUMER data with the 2D 
HINODE/EIS images will provide a perfect temperature coverage 
of the line emissions from chromosphere up to the corona and 
thus allow us to reach our main goal. Combination of the SUMER 
1D and EIS 2D FOVs seems to be optimal for our purpose.

----------------------------------------------------
Predicted count rates:

EIS Exposure duration: 10 seconds

Ion Species    Wavelength     Total counts for exposure
               (A)            (per pixel)

Ca XVII        192.82            0.0
Fe XII         195.12          138.2
He II          256.32           47.4
Si VII         275.35           12.3
----------------------------------------------------

We would be very obliged if the EIS will be able to run
our program with this type of observations. Therefore we
would be obliged to hear from you whether this is realistic
in frame of the SOHO+HINODE campaign scheduled for April
2007 (week 15 in our case).

With best wishes and many thanks beforehand

Peter Gomory, coordinator of the SOHO/HINODE April 2007 program 25

Tatranska Lomnica, 26/03/2007

**************************************************************************
* Peter Gomory                tel.  : ++421 52 7879 166 (111 secretary)  *
* Astronomical Institute      fax   : ++421 52 4467 656                  *
* Slovak Academy of Sciences  email : [email-masked]                    *
* 05960 Tatranska Lomnica     WWW   : http://www.astro.sk/~gomory        *
* Slovak Republic                                                        *
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