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PROGRESS REPORT
THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM
(CONTRACT NAS8-40801)
(for August 1997)
OVERVIEW
The YOHKOH Mission is a program of the Japanese Institute
of Space and Astronautical Science (ISAS) with
collaboration by the U. S. National Aeronautics and Space
Administration and the U. K. Science and Engineering
Research Council. The YOHKOH satellite was launched on 30
August 1991 from Kagoshima Space Center (KSC) in Japan.
The purpose of this mission is to study high energy
phenomena in solar flares and the Sun's corona. Under an
international cooperative agreement, Lockheed, under NASA
contract, is providing a scientific investigation using
the Soft X-ray Telescope (SXT), one of the primary
experiments of the mission. The SXT was developed at the
Lockheed Palo Alto Research Laboratory in cooperation with
the National Astronomical Observatory of Japan, and the
Institute for Astronomy of the University of Tokyo.
MAJOR PROGRAMMATIC ACTIVITIES IN THE MONTH
Preparations are continuing at MSFC to initiate the contractual
modifications to the contract to allow for continued operations in 1998.
The definitization of the NASA budget for FY '98 is also eagerly being
anticipated.
<< Solar Activity >>
This month saw 16 separate numbered active regions. Solar activity is on the
rise.
The month started with medium solar activity, when AR 8069 still produced some
C class flares on the west limb. The GOES background decreased to sub B level
as AR8069 disappeared behind the west limb. The activity level was decreasing
during the first week, although other regions produced a number of B class
flares. As of mid-August, four regions were present on the disk, but none of
them appear to be flare-active.
During the latter half of August, the activity level was low with the GOES
flux staying at low to mid A level. The active region complex AR
8073+8074+8075 showed beautiful loops, but as a decaying region it lacked
transient phenomena.
A bright region rotated on to the NE limb (8076), which was associated with a
filament as seen in the EIT 304 A images. AR 8076 produced several flares up
to M1.4 (30-AUG-97 00 UT). The M1.4 flare showed a short-lived (15 s) spike
in the hard X-ray (~30 keV) light curves. The region stabilized before its
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complexity increased again with new flux emergence. Its southern extension
was identified as AR 8078/8079.
During the last week of August, Solar activity increased. The GOES X-ray
background increased from just below B-level to mid-B-level. There were 7
GOES C-class flares and 1 GOES M-class flare. The was also an interesting
eruption seen above the SE disk from an active region behind the limb on
28-Aug.
The first week of September showed moderate activity. By the end of the week
the GOES level was about B4 and increasing, with a new-cycle region coming
around the SE limb. There were several GOES C-class and M-class flares. The
'active' active region 8076 decayed and went behind the limb on 6 Sep. Two
M-class flares occurred at the end of the reporting period at 18:30 UT 8-SEP
and 10:00 UT 9-SEP.
<< Campaigns >>
During 23-30 August, SXT participated in a campaign between SoHO/CDS
and NAOJ/Norikura to measure the nonthermal velocity along coronal
loops. The coordinated observations took place during passes 4-5.
Three regions were selected as the target, including AR 8076
when it was still near the east limb. Fixed pointing was used.
Requested by H. Hara (NAOJ), we used AlMg and thick Al filters, but
the regions other than AR 8076 were not bright enough to produce
significant signals in the latter filter. Outside the campaign
periods, PFIs were taken in four filters for a better determination
of the plasma parameters.
<< Science >>
Alexander worked on analyzing the Yohkoh data from the Whole Sun Month
campaign. Working with the very faint soft X-ray images at what look like
solar minimum is quite a challenge. The 2nd WSM workshop is to be held at
Goddard in October. He started work on analyzing the EIT and SXT images of
AR7999 for modeling the distribution of T and p for inclusion in the 3D
distribution of magnetic fluxtubes as derived by a potential field
extrapolation.
Canfield finished and submitted a manuscript about twist and writhe in
flux tubes and their relationship to the twist and tilt of active
region magnetic fields, with Pevtsov.
Lemen visited MSSL and worked with folks there on BCS measurements of the
Ca XIX abundance. Bentley had a Cospar paper on this last year and they
are starting to write up a full paper.
Metcalf continued re-reducing IVM data from 1996 June 6 for a collaboration
with Dana Longcope and George Fisher on their SOHO JOP. He also started a
collaboration with Jing Li and John Raymond comparing some UVCS observations
with SXT observations and started work on the HXT MEM/Pixon comparison
paper started at the HXT workshop earlier this year.
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Nitta analyzed all the 36 flares that were studied by Jakimiec, who advocates
the turbulent magnetic field model at the X-ray flare kernel. It is found
that the displacement between the kernel and the low-energy hard X-ray source
is occasionally more than several SXT pixels, so it is likely that the HXT
L-band is looking at higher temperature loops than either SXT or BCS (Fe XXV
and Ca XIX) observes.
<< Public Use of SXT Images >>
We are continuing to make Yohkoh/SXT images available for a variety of uses.
Efforts continue to make selected images available on the Lockheed SXT WWW
homepage (http://www.space.lockheed.com/SXT/). We receive requests for the
Yohkoh posters (#2 and #3) by way of the form on the SXT homepage. Currently
we receive requests via our homepage at the rate of 2 or 3 per day. The WEB
access statistics in August were 35278 accesses and 960 Mbytes transferred.
<< Yohkoh Operations and Health >>
Yohkoh and the SXT continue to function very well. There has been no
further increase in stray light since 25 August 1996.
SXT experienced a normal level of Single Event Upset (SEU) events during the
month:
SXT bit map error 18-Aug-97 Pass 4: 970818-0205
recovered in the 5th pass.
SXT bit map error 27-Aug-97 Pass 5: 970827-0001
recovered in the 6th pass.
SXT sync 1 error 28-Aug-97 Pass 4: 970828-1343
recovered in the 5th pass.
SXT bit map error 03-Sep-97 Pass 1: 970903-0826
recovered in the same pass.
SXT bit map error 06-Sep-97 Pass 1: 970906-0825
recovered in the same pass.
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<< Data Flow >>
Month Full Frame Images Observing Region Images
Received Lost Received Lost Loss %
QT FL Tot
Thru May-95 298612 127932 1270036 347470 1617506 629043 27.66
Jun-95 7210 3087 25251 307 25558 12045 32.03
Jul-95 6418 4145 21180 1639 22819 15109 39.84
Aug-95 7683 2597 26115 2181 28296 10537 27.13
Sep-95 6546 2853 22006 1753 23759 10433 30.51
Oct-95 6937 3502 22177 3853 26030 13044 33.38
Nov-95 5745 2944 21252 517 21769 12119 35.76
Dec-95 6163 2615 24059 901 24960 11652 31.83
Jan-96 6474 2530 27015 1708 28723 14151 33.01
Feb-96 6200 2581 21380 890 22270 10773 32.60
Mar-96 6908 2869 25437 1460 26897 12274 31.33
Apr-96 7172 2124 45445 671 46116 18848 29.01
May-96 6925 2426 30272 1089 31361 12367 28.28
Jun-96 7515 2723 31952 1536 33488 14521 30.25
Jul-96 5954 1995 29886 4769 34655 12427 26.39
Aug-96 7214 3010 21187 1607 22794 9887 30.25
Sep-96 6904 2618 29906 303 30209 12663 29.54
Oct-96 7405 2853 16463 1842 18305 8034 30.50
Nov-96 7001 2296 24292 5395 29687 9340 23.93
Dec-96 7144 2643 25331 2087 27418 10412 27.52
Jan-97 7186 2747 21126 1257 22383 9915 30.70
Feb-97 6016 2034 22097 1072 23169 8961 27.89
Mar-97 7152 1300 26991 1209 28200 6394 18.48
Apr-97 6018 1055 23639 3890 27529 5349 16.27
May-97 7703 1455 29574 3783 33357 7121 17.59
Jun-97 7706 1522 25786 1396 27182 7908 22.54
Jul-97 8614 1385 32503 431 32934 6559 16.61
Aug-97 3380 737 12537 2955 15492 3758 19.52
Sep-97 0 0 0 0 0 0 0.00
Total 481905 192578 1954895 397971 2352866 915644 28.01
Number of Full Frame Images Received: 481905
Number of Observing Region Images Received: 2352866
Total: 2834771
Approximate Number of Shutter Moves/CCD Readouts: 4964382
NOTES: * The loss of images is mainly due to BDR overwrites, but there are also
occasional DSN dumps which are lost.
* It is common to have observing regions which contain more than 64
lines, which requires multiple exposures to make a single observing
region image. This is why the number of shutter moves is larger
than the number of images received plus those lost.
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<< Engineering Summary Table >>
Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical
(DN) (e/sec) Over 48 Over 64 High / # Support Trans
Temp /Days Temp (%)
Jun-95 49.08 696.3 100780 6281 19.6 N/A
Jul-95 49.34 706.2 106408 6628 18.1 N/A
Aug-95 49.72 720.4 114414 7101 19.5 N/A
Sep-95 49.79 723.1 115165 7222 19.6 N/A
Oct-95 50.29 741.9 126452 7911 20.2 N/A
Nov-95 50.11 735.1 122163 7814 25.2 / 2 20.3 N/A
Dec-95 50.19 737.9 123705 7927 22.6 N/A
Jan-96 50.81 761.3 136197 8888 21.5 N/A
Feb-96 50.67 755.8 133263 8705 22.5 / 2 21.5 N/A
Mar-96 50.85 762.9 136982 8973 20.3 N/A
Apr-96 51.14 773.6 142250 9500 19.9 N/A
May-96 51.16 774.4 140697 10018 19.1 N/A
Jun-96 51.56 789.2 147705 10634 20.7 N/A
Jul-96 57.45 1010.2 146293 12228 19.8 N/A
Aug-96 52.58 827.5 165676 12393 19.6 N/A
Sep-96 52.47 823.3 162784 12350 20.0 N/A
Oct-96 52.21 813.8 157689 12047 22.5 / 2 21.3 N/A
Nov-96 52.45 822.9 161683 12534 21.9 N/A
Dec-96 53.08 846.2 171224 13860 22.9 N/A
Jan-97 52.35 818.9 164785 11354 23.8 / 7 23.3 N/A
Feb-97 51.95 803.9 159426 10346 21.1 N/A
Mar-97 55.99 955.6 158428 12190 21.2 N/A
Apr-97 53.14 848.4 176207 13265 20.8 N/A
May-97 52.96 841.7 172052 13094 20.7 N/A
Jun-97 53.69 869.0 182460 14849 19.8 N/A
Jul-97 54.44 897.3 184518 20173 22.5 / 2 21.1 N/A
Aug-97 54.03 881.8 187411 15628 19.8 N/A
Sep-97 N/A N/A N/A N/A 0.0 N/A
NOTES: * The dark current calculations are using full half resolution 2.668 sec
images not taken in during the SAA. The dark current rate assumes a
"fat zero" of 30.5 DN and a gain of 100 e/DN.
* The entrance filter failure of 13-Nov-92 eliminated the capability of
taking optical images, so the optical transmission is not available
after Nov-92. It also caused an increase in the dark current signal,
however some of the increase shown here is an increase in the readout
noise and is not a function of exposure duration.
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<< Personnel Travel >>
SXT Foreign Travel between 1-AUG-97 and 31-AUG-97
HUDSON 1-AUG-97 * 25-AUG-97 25
28-AUG-97 31-AUG-97 * 4
(total of 29 days)
NITTA 1-AUG-97 * 31-AUG-97 * 31
(total of 31 days)
SAVY 1-AUG-97 * 31-AUG-97 * 31
(total of 31 days)
----------------------------------------------------------------
Grand Total of 91 days for 3 people
SXT Foreign Travel between 1-SEP-97 and 30-SEP-97
HUDSON 1-SEP-97 * 14-SEP-97 14
27-SEP-97 30-SEP-97 * 4
(total of 18 days)
LEMEN 21-SEP-97 30-SEP-97 * 10
(total of 10 days)
MCKENZIE 28-SEP-97 30-SEP-97 * 3
(total of 3 days)
NITTA 1-SEP-97 * 3-SEP-97 3
(total of 3 days)
SAVY 1-SEP-97 * 30-SEP-97 * 30
(total of 30 days)
SLATER 26-SEP-97 30-SEP-97 * 5
(total of 5 days)
WUELSER 3-SEP-97 30-SEP-97 * 28
(total of 28 days)
----------------------------------------------------------------
Grand Total of 97 days for 7 people
NOTE: The "*" signifies travel that actually ends after 30-SEP-97
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-------------------------------------------------------------------------------
NASA REPORT DOCUMENTATION PAGE
(IN LIEU OF NASA FORM 1626)
--------------------|--------------------------|-------------------------------
1. REPORT NO. | 2. GOVERNMENT | 3. RECIPIENT'S
DR-01 | ACCESSION NO. | CATALOG NO.
--------------------|--------------------------|-------------------------------
4. TITLE AND SUBTITLE | 5. REPORT DATE
Monthly progress report - for the month of | 10 September 1997
August 1997 |-------------------------------
| 6. PERFORMING ORG
| CODE: O/H1-12
-----------------------------------------------|-------------------------------
7. AUTHOR(S) | 8. PERFORMING ORGANIZA-
T. R. Metcalf | TION REPORT NO:
F. M. Friedlaender |
|-------------------------------
-----------------------------------------------|10. WORK UNIT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS |
Lockheed Palo Alto Research Labs B/252 |-------------------------------
Solar & Astrophysics Laboratory O/H1-12 |11. CONTRACT OR GRANT NO.
3251 Hanover Street, Palo Alto Ca. 94304 | NAS8 - 40801
-----------------------------------------------|-------------------------------
12. SPONSORING AGENCY NAME AND ADDRESS |13. TYPE OF REPORT AND
Marshall Space Flight Center (Explorer Program)| PERIOD COVERED
Huntsville Alabama 35812 | Progress report for the month
| of August 1997
|-------------------------------
|14. SPONSORING AGENCY
| CODE MSFC / AP32
-----------------------------------------------|-------------------------------
15. SUPPLEMENTARY NOTES
-------------------------------------------------------------------------------
16. ABSTRACT
The SOLAR-A Mission is a program of the Institute of Space and Astronautical
Science (ISAS), the Japanese agency for scientific space activity. The
SOLAR-A satellite was launched on August 30, 1991, to study high energy
phenomena in solar flares. As an international cooperative agreement,
Lockheed, under NASA contract, is providing a scientific investigation and
has prepared the Soft X-ray Telescope (SXT), one of the two primary
experiments of the mission.
--------------------------------------|----------------------------------------
17. KEY WORDS (SUGGESTED BY | 18. DISTRIBUTION STATEMENT
AUTHOR(S)) Solar-A, X-ray, CCD, | Space Science, Solar Physics
------------------------|-------------|----------|-----------------|-----------
19. SECURITY CLASSIF. | 20. SECURITY CLASSIF. | 21. NO OF PAGES |22. PRICE
(OF THIS REPORT) | (OF THIS PAGE) | |
None | None | 7 |
------------------------|------------------------|-----------------|-----------
For sale by: Superintendent of Documents, U.S. Government Printing Office