Möglicherweise Full-Halo gestern, 19:36

[Lutz Schenk]

Hallo Zusammen,

gerade trudelt die Halo-CME-Mail herein.

Leider hatte SOHO kurz nach dem Flare Aussetzer, die bis jetzt noch nicht behoben.

Es konnte aber aus sehr wenigen C2 und EIT Frames etwas Halo-artiges ausgemacht werden. Ob noch C3-Bilder folgenwerden weiß ich nicht.
Ausgangspunkt war eine Filamenteruption in AR709.

Hier mal die Mail:

UCMEO 93001 41209 1625/
41208 62026 92126 0001/ 360// 122// 10360
41208 61934 82044 40701 10709 1112/
99999

PLAIN

BT

LASCO C2/EIT observed what it could have been a Full Halo CME
Event on 2004/12/08. Signatures of the potential event were first
observed in C2 at 20:26 UT above the SE and NW limbs (i.e., faint
brightenings). By 21:26 UT the C2 occulting disk is fully
surrounded by a feature that shows up elongated towards NW and SE,
and barely above the NE Limb. A LASCO data Gap occurred afterward
(see Spacecraft Status [*] below). The mean plane-of-sky speed as
measured only on a couple of C2 images was about 360 km/sec at
PA 314.

GOES reported a long duration X-ray event (C2.5) originating from
NOAA AR 10709 (N01W07) between 19:34 - 20:44 UT with peak emission
at 19:59 UT, associated to the event seen on LASCO. EIT 195 images
show a brightening on the AR mentioned above starting at 19:36 UT.
A filament erupts at least partially. Post flare loops form later
across the old filament location. Relatively large dimming region
to E and W of the AR. Last EIT image before Data Gap taken at
21:36 UT.

For completeness, also note that a second X-ray flare (C1.1) was
reported, this time originating on NOAA AR 10710 (S09E49) on
2004/12/09 between 00:09 - 00:15 UT with peak emission at 00:10 UT
(No corresponding LASCO/EIT images).

In summary, the event has therefore been determined as a potential
'full' halo CME, frontsided.

Movies and images (only C2 and EIT 195) of the event will shortly
be made available at:

ftp://ares.nrl.navy.mil/pub/lasco/halo/20041208


[*] Spacecraft Status:

At 21:58 UT telemetry was lost. It was recovered at 22:12 UT in low
rate showing that SOHO is in ESR (Emergency Sun Reacquisition)
mode. The indicated trigger cause is the CSPAAD (Coarse Sun Pointing
Attitude Anomaly Detector). Since all pointing was nominal up to
the point where telemetry was lost this is obviously a false
trigger. The cause is currently unknown. As part of a nominal
recovery from ESR mode, SOHO entered CRP (Coarse Roll Pointing)
mode at 04:44 UT on 2004/12/09. SOHO is still in low rate telemetry.
Recovery is under way.


Best wishes,
Guillermo Stenborg


+--------------------------------------------------+
Dr. Guillermo A. Stenborg
SOHO-LASCO Operations Scientist,
CUA, MC 682.3, Bldg 26, Rm 001, F: +1-301-286-0264
NASA Goddard Space Flight Center,
Greenbelt, MD 20771. P: +1-301-286-2941

e-mail: stenborg@kreutz.nascom.nasa.gov
+--------------------------------------------------+


Viele Grüße,

Lutz

[Bernhard Dorner]

Hallo,

es gab auch einen TypeII-Sweep mit 808km/s. Unten noch der GSE-FF-Lauf dazu.

Viele Grüße
Bernhard
--------
December 9, 2004: Exercise #577 run: December 9, 2004. (Time since #576: 6
days)

#577 occurred concurrently with a CME and a C2.5/SF flare. The metric type
II speed from Palehua was 808 km/s.

The HAFv2. model shows a shock reaching L1 December 11, 2004 with SSI=+0.03
at 0200 UT. The shock should pass Mercury about midday on the 9th. Mars and
Venus will pass a CIR on the 11th, but the shock will decay before arrival.
See the movie at http://gse.gi.alaska.edu/recent/javascript_movie.html

The STOA model predicts a travel time of 53h 09m, for a Mach 3.5 shock to
arrive at Earth on December 11, 2004 at 0054 UT.

Other models in the ensemble, some maintenance issues and weekend services
are not always available until further notice because of program funding
shortfall.


Inputs for model HAFv.2 and STOA are:
# Date Start Time Location Vs Tau Vsw
NNNN YYYYMMDD HHMM LAT LON VS TAU VSW SIGMA XMAX XEND OPT XRAY
0577 20041208 1945 N08 W03 808 0300 450 XXX XXXX XXXX SF C2.5

[Lutz Schenk]

Hi Zusammen,

Beim STD eine Ankunftsvorhersage und sogar ein Mid-Lat-Watch aktiv.

Aber alles mit sehr verhaltenen Aussichten, dem Event schon entsprechend, wohl aber auch auf Grund der leider sehr mageren Datenlage. Aber von einem C2 ist wohl auch nicht allzu viel zu erwarten.

Hier mal die Vorhersage:

Event #69 - 09 December 2004

Issued: 23:00 UTC, 09 December 2004

SOURCE EVENT

C2.5 LDE from Region 10709 on 08 December 2004
Type II: 808 km/sec
Estimated LASCO-derived Plane of Sky Velocity: 360 km/sec

ESTIMATED TIME OF ARRIVAL OF SHOCK AT EARTH


Estimated Impact Window: 00:00 UTC on 11 Dec to 12:00 UTC on 12 Dec
Preferred Predicted Impact Time: 18:00 UTC on 11 December (1:00 pm EST on 12 Dec)
Estimated Shock Strength (0=Weakest, 9=Strongest): 1-2

Predicted Behavior of IMF at Shock Impact

At Shock Impact, the Interplanetary Magnetic Field is predicted to initially turn:
NORTHWARD

EVENT #69 NOTES:

A full-halo coronal mass ejection was observed leaving the Sun late on 08 December following a long-duration class C2 solar flare from Region 10709. This event is in all likelihood fairly slow moving. This increases the uncertainty of the time of arrival. Without further LASCO data to examine (SOHO suffered an emergency sun reacquisition anomaly and likely will not be able to provide any further imagery for this particular event - SOHO is in recovery mode), our best estimate is for sometime near 18:00 UTC on 11 December, give or take 6 to 12 hours. The impact is not expected to be particularly significant, although there is a chance the ensuing plasma cloud could produce periods of storm-level geomagnetic activity after it arrives. K-indices of 3 to 4 are expected to dominate, with excursions to 5 (and a slight chance of brief K-indices of 6) considered possible. There is a good chance the Earth will intersect a magnetic cloud with this event.

These predictions may be based on preliminary data and may be revised without warning. The predictions should not be used as a definitive indication of CME impact times or strengths and may frequently be in error. The proprietary methods used to estimate shock impact times are under continual development. Caution is advised.
----------------------------------------------------------

Und hier der Watch. Ist zwar als Mid-Lat deklariert, es sind aber eher die sehr nördlichen Mid-Lat's angesprochen:



MIDDLE LATITUDE AURORAL ACTIVITY WATCH
Issued: 04:10 UTC, 10 December 2004
Solar Terrestrial Dispatch
www.spacew.com


VALID BEGINNING AT: 00:00 UTC (7 pm EST) 11 DECEMBER
VALID UNTIL: 23:00 UTC (6 pm EST) ON 13 DECEMBER

HIGH RISK PERIOD: 12 DECEMBER
MODERATE RISK PERIOD: 11-13 DECEMBER

PREDICTED ACTIVITY INDICES: 10, 24, 16, 12 (10 - 13 DECEMBER)

POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: LOW-MODERATE

POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 18 TO 24 HOURS
MINOR BELT = 24 TO 36 HOURS

ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR LOCAL MIDNIGHT

EXPECTED LUNAR INTERFERENCE: NONE

OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR

AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...

SOUTHERN BRITISH COLUMBIA TO MONTANA TO NORTHERN SOUTH DAKOTA TO
MINNESOTA TO WISCONSIN TO MICHIGAN TO EXTREME NORTHERN NEW YORK STATE TO
VERMONT TO MAINE.

ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...

NORTHERN SCOTLAND TO NORTHERN DENMARK TO SOUTHERN NORWAY TO
SOUTHERN SWEDEN TO SOUTHERN FINLAND TO NORTHERN RUSSIA.

ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY SOUTH OF A LINE FROM...

SOUTHERN NEW ZEALAND.


SYNOPSIS...

An earthward directed coronal mass ejection is expected to increase
levels of auroral activity on 11 and 12 December (UTC days). This is a slower
moving coronal mass ejection and probably won't have a significant impact.
Nevertheless, it may have the potential to produce periods of minor
geomagnetic and auroral storming over the high and some middle latitude
regions, particularly on 12 December. The strongest period of auroral
activity should be observed over North America during the local evening hours
of 11 December (which corresponds to the early UTC hours of 12 December). The
slower nature of this disturbance means that conditions may remain capable of
producing visible levels of auroral activity through a portion of 13
December.

This watch will remain valid through 23:00 UTC (6 pm EST) on
13 December. It will then be allowed to expire. For updated information,
visit: http://www.spacew.com/aurora/forum.html. For real-time plots of
current activity, visit: http://www.spacew.com/plots.html or
www.sec.noaa.gov.

PLEASE REPORT OBSERVATIONS OF AURORAL ACTIVITY TO:
http://www.spacew.com/submitsighting.html


** End of Watch **

Viele Grüße,

Lutz

[Ulrich Rieth]

Hallo Lutz!

Also als ich den Watch gelesen habe, hab ich mich schon wieder etwas gewundert, wieso der überhaupt ausgegeben wird.
Daher hab ich ihn heute morgen auch nicht gleich hier rein gepackt.
Der Sonnenwind ist auch schon wieder dünn und langsam, also wird das Teil vermutlich wieder nicht in den ACE Daten auftauchen.
Insgesamt, auch wegen der im Watch genannten Grenzen, sicher ein Ereignis dem man nichtmal Aufmerksamkeit schenken muss.
Aber wer mag, kann ja mal die EPAM Werte im Auge halten und Bescheid geben, wenn sich was tut.
Gruß

Ulrich

[CarstenH(carhu)]

Hallo!

Signatures of the potential event were first
observed in C2 at 20:26 UT above the SE and NW limbs (i.e., faint
brightenings). By 21:26 UT the C2 occulting disk is fully
surrounded by a feature that shows up elongated towards NW and SE,
and barely above the NE Limb.

Hierzu mal ein C2-DIFF aus 20041208_2006_c2.gif und 20041208_2126_c2.gif.

Ich sehe da keinen "Full Halo" (kennt eigentlich jemand ein deutsches Wort dafür?).


Mit besten Grüßen

Carsten

[Bernhard Dorner]

Hallo nochmal,

heute kam die zugehörige schwache Front an (IPS-Meldung):

Code: Alles auswählen

WEAK SHOCK DETECTED IN SOLAR WIND AT 11 12 2004 1255UT
      Mean Solar Wind Parameters Pre/Post Shock:
                               Pre        Post     Pre/Post
      Param.    Unit           Shock      Shock    Change
      Density   part/cc          1.8        4.8        3.0
      Velocity  km/sec         461.4      503.7       42.3
      Temp      Degree K     58207.4   123233.3    65025.9
      Bt        nT               3.8        6.7        2.9
      Bz        nT              -2.1       -4.8       -2.6
ACE status at shock detection point:
ACE SWEPAM status: Data values are Nominal
ACE MAG status: Data values are Nominal
=========================================================================
Confirm event at http://sec.noaa.gov/ace/MAG_SWEPAM_24h.html

Ciao
Bernhard