Sorry about forwarding one of these again, but I get these all the time being a hires-1 operator and these solar people NEVER give us more than a laconic third-person paragraph during solar activity. This is pretty interesting that they have measured the largest solar flare just last Thursday.
No, we measure cosmic rays, not solar flares. Solar activity can definetly degrade the sensitivity of our detectors. them: http://bbso.njit.edu/ us: http://cosmic-ray.org/ Justin ---------- Forwarded message ---------- Date: Fri, 7 Nov 2003 11:54:23 -0800 From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: BBSO Solar Activity Warning 07-NOV-2003 18:18:38 UT For those of you with interests in the recent solar activity, Alan Kiplinger, Center for Integrated Plamsa Studies, U. of Colorado and NOAA/SEC, has provided us with his discription of this remarkable solar activity. At approximately 19:29 UT on 04 Nov. 2003 the Sun began an eruption in NOAA region 0486 at S19W86 of the largest solar flare ever recorded in soft X-rays (see http://www.bbso.njit.edu for a movie of the flare obtained at the Big Bear Solar Observatory of the New Jersey Institute of Technology). By 19:44 UT, NOAA's GOES 12 satellite reached saturation at X-17.4 (1-8A) an remained saturated until 19:55 UT. In order to estimate the actural peak intensity, I compared this flare's behavior with earlier flares from the same region. The three prior X-class flares occurring on 02 and 03 Nov. had much slower rise and decay times when compared on log plots of intensity. However, the X-10 flare of Oct. 29 matched the rise and decay times of the 04 Nov. flare almost precisely over a 50 minute period spanning the peak. By superimposing the curves, I deduced that the flare reached X-28 (+/- 3, a conservative error estimate) at 19:47 UT. Independently, Dr. Rodney Viereck of NOAA/SEC fitted the rise and decay curves with polynomial and log-normal functions and arrived at peak flux values ranging from X-25 to X-31. Accordingly, NOAA/SEL has tagged this flare as an X-28 (estimated) which makes it the largest soft X-ray flare ever recorded. The coronagraph at Sacramento Peak Solar Observatory also recorded the most intense coronal emission that it has ever seen. Very fortunately, the region was located extremely close to the west limb; thus, it was not magnetically well connected to us and effects at Earth were not terribly dramatic or destructive. Don Neidig (AFGL/PHL) at sacramento Peak Observatory reports that the ISOON H-alpha telescope recorded point brightenings that progressed to the south pole in association with the flare. Sara Martin (Helio Research) commented that the SOHO 175A images from EIT showed simultaneous darking of coronal hole areas at the south pole and darking of a north-south area (channel?) near the central meridian and just above the equator. This indicates that the region is globally connected. The comparison X-10 flare of 29 Oct. from AR 0486 is equally interesting. Brian Dennis (NASA/GSFC) reports that the flare is, by far, the most intense gamma ray line flare observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). RHESSI missed the peak of the X-28 event. The X-10 flare also was well observed by ISOON. Don Neidig reports clear evidence for a Morton wave as observed in on-band and +/- 0.4A off band patrol images. The wave can be seen in the direct images but is best seen by subtracting the red minus blue off-bandimages. The wave proceeded from the region to the north-east with a cone angle of about 50 degrees. It was not just a single front, but a wave train (like a moving washboard) with about three or four waves. The speed was 1100 km/sec, wavelength 88000km, peroid 80s, and data indicate vertical amplitude changes of roughly 66 km. We interpret the wave train as a mechanical oscillation of chromospheric material due to compression from the Morton wave. Sara Martin also reports that there were simultaneous darkenings near the south pole as recorded by SOHO's EIT at 175A, thus confirming regional global connections. There was a large westward coronal mass ejection (CME) associated with the X-28 flare on 04 Nov. This flare associated CME was proceeded by a halo CME occured ~17:00 to 18:00 UT on Nov. 06. Region 0484 produced 2 X- and 16 M-class flares and is due to return ~ Nov. 12. Region 0488 produced X- and M-class flares. Thus, it is most likely that the show is not over. Alan Kiplinger, November 07, 2003 W. Marquette, BBSO/NJIT ____________________ BYU Unix Users Group http://uug.byu.edu/ ___________________________________________________________________ List Info: http://uug.byu.edu/cgi-bin/mailman/listinfo/uug-list
