We propose simultaneous measurements of SUMER and CDS spectrometers for an interval of few hours and for several days in order to acquire sufficiently large material. This material is necessary for the studying of the variability and behaviour of spectral lines in the particular phenomena. The required MDI operation providing the photospheric information on interval of few hours is essential for the understanding of these phenomena. If the TRACE (or alternatively EIT) could cooperate with the proposed SOHO JOP at least for a part of the SOHO observing runs, it will be also very important.
The SUMER should use a fixed 1D slit position. The CDS should mostly provide information from a 2D FOV pointed around the SUMER position in order to overlap SUMER and CDS data post-facto. Special measurements, incorporated to this JOP, are proposed to reach a more precise determination of the SUMER slit position in the CDS 2D FOVs (the practical precision of CDS and SUMER pointing is roughly 5'').
The photospheric physical quantities are proposed to be measured with the MDI instrument simultaneously on a more extended FOV (300''x500'') than in the case of SUMER and CDS instruments (SUMER : 1''x120'', CDS : from 2''x140'' to 124''x244''). The proposed TRACE operation includes also the collection of photospheric continuum images. The extended SUMER RSC measurements are scheduled for the co-alignment of the SUMER slit position with the photospheric images taken by MDI and TRACE.
SUMER and CDS observations are proposed to be carried out various modes (sequence parts) to determine both the temporal and spatial behaviour of the spectral lines. The MDI and EIT observations are proposed to be performed in a single mode over the whole JOP run. TRACE should work in 2 different modes carried out sequentially.
Basic summary of the simultaneous SOHO(MDI/SUMER/CDS/(EIT)) and TRACE operations :
Target region : the disk center, quiet region covering both the supergranular boundary and the internetwork, inside and outside of the equatorial coronal hole if possible.