GONGMagnetograms and

Coronal Field Modeling

G.J.D. Petrie, J. Bolding, R. Clark, K. Donaldson-Hanna, J.W. Harvey, F. Hill,

C. Toner & T.M. WentzelNational Solar Observatory,

Tucson, AZ 85719

Background• GONG (Global Oscillations Network Group)

obtains 2.5’’-pixel intensity, velocity and magnetic flux images every minute from six sites worldwide

• approximately 90% duty cycle• continuous, high-cadence, low-noise photospheric

line-of-sight magnetograms• new LCD modulators and circuitry reduced

uncertainty in zero-point < 0.1 Gauss, instrumental noise about 3 G/minute

• GONG is the official provider of magnetograms for NASA’s STEREO mission.

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Near-real-time GONG potential magnetic field

products• Principal features of global coronal field structure are

calculated and plotted.• We thank Janet Luhmann, Yan Li and Xuepu Zhao for

source code used in the modeling.• Green represents positive polarity and red negative

polarity.• Features include coronal holes, streamer belt,

heliospheric current sheet and lines open to the ecliptic plane

• Products are produced once per hour, and movies are available at

http://gong.nso.edu/data/magmap/index.html

GONG magnetogram and modeling products to expand

• More ideas are being implemented and more are welcome

• GONG Magnetogram Users’ Group (MUG) meeting today 6.30 pm foyer

• Please exploit this new round-the-clock source of sensitive, high-cadence data http://gong.nso.edu/data/magmap/index.html