Subject: 'Full' Halo CME on 2004/04/06, frontsided

From: Guillermo Stenborg <[email-masked]>
Date: Tue, 6 Apr 2004 15:04:07 -0500 (EST)

UCMEO 93001 40406 1910/
40406 61331 91742 0001/ 360// 123// 41075
40406 61230 81346 21518 10588 1222/
99999

PLAIN

BT

LASCO and EIT observed a full halo CME on 2004/04/06.
The event was first observed in C2 at 13:31 UT as a bright
loop front in the SE; by 14:06 UT the front has developed 
into a full halo CME, though rather faint in the NW.
The front first appeared in C3 images at 14:18 UT with 
full coverage of the C3 occulting disk by 15:18 UT. The 
mean plane-of-sky speed for this event at PA 163 was 
1075 km/s showing a slight positive acceleration in C2 
FOV and a slight deceleration in C3 FOV. For reference, the 
mean plane-of-sky speed at different PA as obtained from C3
measurements is given below:

PA 000: 417 km/s
PA 050: 526 km/s
PA 120: 733 km/s
PA 210: 559 km/s
PA 246: 558 km/s

The CME was most probably associated with a M2.4 X-ray flare
that GOES records from AR 0588 (by the time at S18E15) 
between 12:30 - 13:46 UT with peak emission at 13:28 UT.
EIT Fe XII runnning difference images show signatures of 
the events between approximately 12:36 and 15:48 UT, the
flare peaking at 13:25 UT. Moreover, a large disturbance 
traveling outward (CME signature) can be distinguished 
after the flare peak. No dimming was observed in association 
with the event. This event has therefore been determined 
frontsided. 

Movies and images of this event will shortly be available 
at:

ftp://ares.nrl.navy.mil/pub/lasco/halo/20040406

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: [email-masked]
+--------------------------------------------------+