JOP 152 Multi-wavelength Observations of Large-scale Shock Waves on the Sun Version History: 1; 2 February 2002 Contacts -------- Josef I. Khan (khan@solar.isas.ac.jp) Therese Kucera (terry.kucera@gsfc.nasa.gov) Hugh S. Hudson (hudson@isass1.solar.isas.ac.jp) Instruments ----------- SOHO CDS & EIT; TRACE Schedule -------- Begin Date: Preferably sometime in February prior to HESSI support observations End Date: TBD We request a two-week observation period, but will accept a one-week or shorter period. We have a slight preference for the time interval 08:30-14:00 UT to overlap the interval of routine radio observations of the Nancay Radioheliograph, and various high quality radio spectrographs in Europe. Such additional observations would be very useful in confirming the type II radio burst. In addition, we would like the CDS & TRACE observations to be kept available as a target of opportunity (at relatively short notice in the future, if such observations are possible) if a type-II-productive region appears, assuming CDS or TRACE are not too busy with other campaigns or operations. Scientific Objective and Justification -------------------------------------- The broad objectives of this JOP are to detect signatures of shock waves at different wavelengths and at different heights in the solar atmosphere. Such waves have been observed as type II radio bursts and EIT waves, while H alpha Moreton waves are believed to be a chromospheric feature associated with the coronal shock wave. Shock waves have also been observed in TRACE 195 and 171 A images and in Yohkoh SXT images. Recent work on one event observed with SXT, EIT and H alpha (Khan & Aurass, 2001, A&A, in press) indicates good agreement, but others have reported differences between EIT waves and Moreton waves, such as frequency of occurrence, inferred speeds, and differing locations. The main aim of the JOP, at this stage, is to detect large-scale shock waves (aka flare waves) with the SOHO CDS and TRACE and also the SOHO EIT. The EIT and TRACE observations of waves will be used as a proxy for the shock wave where no other data sources are available. In future versions of this JOP we anticipate coordination with ground-based observatories to examine the relations between H alpha Moreton waves, type II radio bursts, etc. In this first run, we aim to determine the best lines to detect such waves with CDS and also to detect Doppler shifts associated with such waves. Spectroscopic data from CDS may help resolve whether there are differences between EIT and other waves. Doppler shifts are expected from Uchida's sweeping skirt model for Moreton waves but have not been observed to date. Spectroscopic observations may also help resolve the debate about whether EIT waves are related to shock waves or effects associated more directly with coronal mass ejections. Target ------ Outer vicinity of an active region. Defining Properties ------------------- At the location where an EIT/TRACE wave was observed previously (or is anticipated) from a flare-productive, metric type-II-productive active region. Target Position --------------- This will be based on an EIT wave & H alpha Moreton wave observed previously. If no EIT wave was observed recently then best guess where wave may occur will be given. In such a case, we suggest observing a region to the N, NW or NE of an active region in the southern hemisphere, or to the S, SW and SE of an active region in the northern hemisphere (i.e., towards to center of the disk). Detailed Observing Sequences per Instrument ------------------------------------------- SOHO CDS -------- We require NIS only. First we wish to establish which lines can best see EIT/shock waves. This is not so obvious, a priori. Therefore we will select a variety of lines across a range of temperatures. We aim to detect the shock wave as a feature of enhanced intensity and as a feature showing Doppler motions (red or blue-shifts) in relatively cooler lines as might be expected from Uchida's sweeping skirt model for Moreton waves. CDS Observing Sequence: Lines: Si XII 520.665 A 10^6.3 K O IV 554.52 A 10^5.2 K Ne VI 562.803 A 10^5.6 K He I 584.33 A 10^4.3 K O III 599.59 A 10^4.9 K He II 303.78 A (2nd order) 10^4.7 K Mg X 624.94 A 10^6.1 K O V 629.73 A 10^5.3 K Ca X 557.7 10^6.0 K Ne VII 558.6 10^5.7 K Mg IX 369.07 10^6.0 K Slit size: 4x240 Program: A sit and stare observation with occasional rasters for context. 44.5 sec exposures TRACE ----- TRACE will be used to confirm the CDS shock wave detection and also to observe it with high spatial and temporal resolution. In view of the current anomaly of the TRACE quadrant selector mechanism we will use only the single 195 A quadrant in the initial run. We require a sequence of relatively deep 195 A observations using the full FOV of full resolution of 1024x1024 pixels, with an exposure cadence of approximately 45 seconds. In future runs, depending on the situation with the TRACE quadrant selector mechanism and the results from the CDS observations, we may like to extend the observations to other wavelengths, namely 171, 1550, 1600 or 1700 A. The TRACE FOV should substantially overlap the CDS slit. SOHO EIT -------- Standard EIT observations which are currently optimized for EIT wave detection with 195 A are sufficient. Although we do not request special observations, the EIT observations are very important for this project to confirm the shock wave detection in CDS.