SOHO Joint Observing Programme 073

				BLINKERS

Authors: R.A. Harrison (CDS), K.J.H. Phillips (CDS), R. Bush (MDI),
T. Tarbell (MDI), P. Gallagher (Belfast), L. Harra-Murnion (MSSL)

Progress:
	First Draft	November 14 1997


Objective:
	A thorough investigation of the phenomenon which has become
	known as the blinker - i.e. transient brightenings in the
	quiet Sun network.

Conditions Necessary to Run:
	CDS can run this alone, but high reolution magnetogram data
	from MDI would be extremely valuable, and the shorter the
	cadence the better. Similarly, EIT context images would be
	extremely valuable.

Scientific Justification:
	CDS quiet Sun, rapid rasters have revealed small brightenings
	within the quiet Sun network. This 'microflare' events have 
	been reported by Harrison (1997, October issue of Solar Physics).
	Dubbed 'blinkers', these events appear to be widespread with
	up to 300 on the solar 'surface' at any point in time. Initial
	observations have revealed little effect at high (million K)
	or low (tens of thousands K) temperatures. The events are mainly
	observed in the few hundred thousand K range and appear to be
	not associated with flows.
		How do these blinkers relate to the high velocity events
	seen by SUMER and HRTS? So far, we believe they are totally
	unrelated! How do they relate to the observation of Network
	Flares seen by Yohkoh? How do they relate to the magnetic
	features seen by MDI and, in particular, can they be related
	to the merging magnetic flux at cell boundaries.
		We may be seeing the thermal output from a most basic
	process which is occurring within the solar atmosphere. As such,
	they may be closely associated with coronal heating and wind
	acceleration processes.
		Further study demands a close exmaination of EUV and
	magnetic data, an extension of the EUV data to lines from more
	temperatures, and greater duration studies. This is the purpose
	of this JOP activity.

Pointing:
	Three sequences are suggested. For each, we must direct CDS to
	the MDI high resolution field and to a pointing which will
	remain as quiet Sun through the observing period.

Operating Details:

	CDS:  Three 'parts' are given to this JOP. They need not
		be run in series. Each is a seperate investigation.

		Part 1:  Duration 4-5 hours per run. To Study
		basic transient activity.
		First, run large area, deep raster (INT_DIST - Study
		ID 11, Variation 26) to map 4x4 arcmin region.
		Second, run 3-4 hours of smaller, 'quick' rasters,
		BLINK_ST (if CDS in standard telemetry rate) or
		BLINK_HI (if in high rate). Both are 40x100 arcsec
		fields with 2-3 minute cadence and 6 or 9 emission
		lines.

		Part 2: Duration about 9 hours per run. To study
		rapid transient activity.
		First, run large area, deep raster (INT_DIST - Study
		ID 11, Variation 26) to map 4x4 arcmin region.
		Following this, run a sequence of small rasters
		using NTBRMDI1 and NTBRMDI2 Studies.

		Part 3: Duration 10+ hours. To study slowly
		varying transient activity.
		Run a long series of INT_DIST (Study ID 11, Variation
		26) over many hours, preferably greater than 10.	
		This is a 4x4 arcmin raster over 47 minutes.

	MDI:	Magnetic observations required in high resolution field
		either in standard synoptic mode, or enhanced cadence.

	EIT:	Supporting synoptic data from all four wavelength
		bands, in particular a series of Fe XII images 
		through the observing sequence.