JOP227 Doppler shift oscillations of AR loops Authors: D.E. Innes, S. Kamio (Update on JOP 104. Now with STEREO, Hinode, SDO) Intruments and POCs SOHO/SUMER: D.E. Innes HINODE/EIS: S. Kamio HINODE/XRT: STEREO/SECCHI: SDO: Scientific Objectives: 1: To observe Doppler shift oscillations in limb active region loops together with high cadence, multi-filter AIA/SDO observations and STEREO disk observations of the same loops. 2. To test the slow mode interpretation of Doppler shift oscillations seen in coronal loops above the solar limb at flare onset. Scientific Background: There have been many observations of Doppler shift oscillations in active region loops by SUMER and EIS. The SUMER observations were mostly in the years 2000 to 2003 during the last solar maximum. The oscillations were seen in the lines, Fe XIX 1118 A and Fe XXI 1354 A at the onset of C, M and X flares. The current interpretation is that the oscillations are caused by microflaring at loop footpoints triggering a standing slow mode wave in the active region loop. Now with the two STEREO spacecraft making an almost 90 degree angle to the Earth-Sun line we have the possibility to test this interpretation because STEREO will reveal the face-on view of the oscillating loop and triggering microflare. AIA images will provide the necessary limb view of the loop dynamics. The chances of capturing a flare on the solar limb are increasing with the start of the new cycle. Although flares are not nearly as frequent as in 2000-2003, we have a greater chance over the previous SUMER campaigns of being in the right place. We can use STEREO to see active regions coming around the East limb and we can point to the most likely flare producing region. In 2000-2003, SUMER was not moving in azimuth so we had to wait until an active regions rotated to the chosen limb. In June SUMER will be moving in azimuth, at least doubling our chances of observing at the right place. Operational Considerations: These observations require a limb active region as seen from SoHO. If there is not limb active region during the scheduled time then we will observe prominence activity. A typical observation is 8 hours. Proposed Dates: 2010 Jun 20 ñ Jun 30 during the planned SUMER campaign. Detailed Observing sequences: SOHO/SUMER - context raster followed by 8 hours of sit and stare about 60 arcsec off the limb in the corona, observing the lines Fe XVIII 974.84, Ca XIV 943.63, S X 946.32, Si IX 950.16, Si VIII 944.35, 944.63, 949.24, C III 977.03, H I 949.74, 972.54 Hinode/EIS: Context raster and sit and stare 30 arcsec off the limb in the corona, observing the lines Fe XXIV 192.03, Fe XXIII 263.76, Ca XVII 192.82, Fe XVI 262.98, Fe XV 284.16, Fe XIV 274.20/264.79 , Fe XII 195.12, Si VII 275.35, He II 256.32 Hinode/XRT: Al-poly, Be-thin FOV: 384''x512'' Cadence: 60 s over a period of 8 hours STEREO: SECCHI High cadence if possible. SDO: Synoptic