HOP 0180
	
Dynamics and physical properties of large scale coronal waves ("EIT waves")

abstract of observational proposal
 "EIT waves" are large-scale disturbances in the solar corona propagating with mean velocities in the range 200-400 km/s. 12 years after their discovery (Thompson et al. 1998) there is still an ongoing debate about the physical nature of the phenomenon: are "EIT waves" indeed proper waves (fast-mode MHD waves) or just signatures related to the erupting CME and associated large-scale magnetic field reconfiguration (so-called "pseudo-wave" hypothesis). One important reason why there is still so much controversy on this subject is the low cadence of the EIT/SOHO instrument (12 min), which does not allow us to properly study the kinematics and dynamics of these events. These limitations are now overcome by a number of full-disk EUV imagers observing the Sun: STEREO EUVI, Proba-2 SWAP, and most recently SDO AIA. The other important reason is the missing plasma diagnostics for "EIT waves".
  In the proposed project, we plan to combine EUV imaging observations of "EIT waves" by  Proba-2 SWAP and SDO AIA with high cadence (<1 min) in various chromospheric, transition region and coronal spectral lines with high-cadence Hinode EIS spectroscopic sit-and-stare data. Our main aim is to study the plasma motions below the propagating wave fronts with EIS, in transition region and coronal lines together with plasma density diagnostics. To this aim will place the 512 arcsec EIS slit outside an active region (in North-South direction), in order to follow the evolution of EIT waves propagating across the slit. This will allow us to study the plasma conditions, compression ratios and plasma motions related to EIT waves together with their kinematical behaviour. This combined imaging and spectroscopic approach would provide important diagnostics on the physical processes underlying EIT waves, and would be most helpful to pin down the wave vs. non-wave debate.

 request to SOT

 request to XRT

 request to EIS
 STUDY TITLE: Dynamics and physical properties of EIT waves.
 TARGET/POINTING: surroundings of active regions,
                  exact pointing will be specified well in advance
                  according actual situation        
 EXPOSURE TIME: 45 s (for both sit-and-stare and context part of
                      the observations)
 SLIT: a) sit-and-stare mode: 2"
       b) context images: 40" (slot)
 COMPRESSION: DPCM (for the whole observing run)
 NUMBER OF STUDIES: 2
  1) study eis:eitwave_obssns   - sit-and-stare mode; FOV: 2"x512"
  2) study eis:eitwave_context  - context images, FOV: 80"x512",
                                  step size: 40", slot: 40"

 USE/INSTRUCTIONS TO PLANNERS:
     STUDY NAME                                       RASTER NAME
 eis:eitwave_obssns:  consists of only one raster  eitwave_search_sns
 eis:eitwave_context: consists of only one raster  eitwave_context_map

 Ordering of the studies (with no. of repeats) :

          STUDY                RASTER         TIME
 1. eis:eitwave_context  eitwave_context_map  2m1s  
    - optimum number of study repetitions: 3
    - total duration: 6m3s
    - data volume: 1.1 Mbit

 2. eis:eitwave_obssns   eitwave_search_sns   33m11s    
    - optimum number of study repetitions: 8 (or as many as possible)
    - total duration: 4h25m28s
    - data Volume: 289.6 Mbit

 3. eis:eitwave_context  eitwave_context_map  2m1s  
    - optimum number of study repetitions: 3
    - total duration: 6m3s
    - data volume: 1.1 Mbit


 Total time:  4h37m34s
 Data Volume: 292 Mbit (total)

 PREFERRED OBSERVING TIME SLOT: depends mainly on coordination with the
                                Proba-2 SWAP instrument

 PREFERRED POINTING: close to active regions; will be specified in advance
                     according actual situation

 SCHEDULING OF THE PROGRAM:
 Program is prepared according to new study Submission requirements. The
 planners are free to change number of repetitions of the study 2., in
 the ordering of studies above, in order to allow an optimum interruption
 of the program due to the instrument specific uploads, etc.
*******************************************************************************
 Predicted count rates: Quiet sun; exposure time: 45s.
 Note: we expect higher count rates than counts obtained for the quiet Sun
       listed below as we plan to observe close to active regions.

 table of selected spectral lines proposed for the sit-and-stare observing
 sequence (main scientific part of the proposed observations)

 Wavelength   c/p     Ion      Total counts for exposure (per pixel)
   186.88      p     Fe XII                  95.4
   192.82      c     Ca XVII                  0.0
   195.12      c     Fe XII                1243.8
   196.53      p     Fe XIII                 45.9
   202.04      p     Fe XIII                156.6
   203.82      p     Fe XIII                 74.7
   256.32      c     He II                  426.6
   262.98      p     Fe XVI                   3.6
   275.35      p     Si VII                 110.7 -> FeXII 192.39
   278.39      p     Mg VII                  56.7 -> SiX 258.37        
   280.75      p     Mg VII                  23.4 -> SiX 261.04 (14-feb-13)


 table of selected spectral lines proposed for the context part of
 observations (acquisition of the context images mainly for the
 coalignment purposes)  

 Wavelength   c/p     Ion      Total counts for exposure (per pixel)
   192.82      c     Ca XVII                  0.0
   195.12      c     Fe XII                1243.8
   256.32      c     He II                  426.6

 other participating instruments
Proba-2 SWAP

 remarks
Target of interest:          
 o target of interest: surroundings of active regions; exact target will
   be specified well in advance depending on the actual solar activity
 o chance to have the target: we expect that increasing solar activity
   will allow to observe our target each day
 o target of opportunity (TOO): no