HOP 0002

abstract of observational proposal

○Objective: To characterize the temperature, dynamics and statistical distribution of polar coronal jets recently observed by XRT.

Scientific Justification: Recent observations of the north polar coronal hole have shown highly dynamic and frequent (numerous per hour) x-ray jets. This apparently originate from small ephemeral regions within and near the coronal hole boundary. These jets may be the final phase of reconnection; produced when a bi-pole emerges into a predominately open flux region. The previous observations of XRT, taken on 23 November 2006, capture some 44 of these events in a roughly 6 hour period. Estimates of the mass-loading into the IMF based upon a density assumption of 10^9 and volume put the mass flux at just under an order of magnitude of the fast solar wind. These two realizations, the so-called 'Shibata-type' reconnection events and the contribution of mass to the solar wind, are sufficient justification for this observation request.

○Motivation: ・North and south limb HINODE/SP data have shown a conspicuous presence of small magnetic fields structures that has not been detected up to now.・There is a strong interest in determining the magnetic structure and origin of these magnetic features, besides their relationship among the four cardinal points. ・Disk center SP data have also shown a opulence of small scale flux tube concentrations with may be connected to north and south poles magnetic activity.

request to SOT

G-band and Ca-H at high cadence full resolution with vector magnetograms.

○4.8 x 4 seconds integration time needed in SP to increase the SNR a factor of 2 on the limb
Time evolution of granular structures are ~ 1 min.
80"x120" maps will take 4 hours in total
5 positions (North, South, East, West, disc center) with no active regions.
West limb have been only once observed and East limb never !!!
At least high resolution G-band maps (1x1) to identify magnetic features.

request to XRT

High cadence observations in a single filter (Al-poly) with a 1024 x 384 field of view. 16.34 sec exposures have already been tested for this type observation. Also, context images with a field of view of 1024 x 960 (offset relative to the pointing position) are required to extend the field of view to 0.7 solar radii. This is the expected slit position of the UVCS instrument on SoHO.

request to EIS

Slot images in Fe VII - Fe XV and He II are appropriate. The smaller slot (40") should provide the best temperature information while extending the field of view to a size large enough to capture some of the events. A 'picket fence' type raster scan may also be appropriate if 6-8 slit positions are selected at x positions [-15,-10,-5,0,+5,+10,+15] arcsec from the zero longitude.

other participating instruments

UVCS: spectral line intensities for doppler dimming and velocity measurements　with a slit position orthogonal to solar north
CDS: Observations with the 2" slit using the line list in JOP 146. It would be useful to use the same slit positions as EIS.
TRACE: 1711 1024 x 1024, Q4 @ 30s cadence with 1600 or 1550 & WL in context.
LASCO: TBD

○inner Hinode