An Incident on the Sun

Read Laboratory Exercise 6, section 4 and answer questions 22-24.

Figure 6.18

Twisted magnetic fields erupted above a sunspot on Thursday, July 18, 2002. The explosion sparked an X2-class solar flare and hurled a faint coronal mass ejection (CME). The CME arrived on July 19th and triggered a period of faint high-latitude auroras. This picture was taken by Dominic Cantin, 75 km north of Québec City, Canada July 19,2002.

three clusters of twisted magnetic fields on surface of the sun

Shortly thereafter, on July 20, 2002, a powerful X3-class solar flare erupted from a location just behind the Sun’s southeastern limb. The explosion, which was most intense at 21:30 UT (2:30 p.m. PDT), caused a radio blackout across North America and the Pacific Ocean.


Figure 6.19

Below is a Hydrogen Alpha spectroheliogram from the Big Bear Solar Observatory (BBSO). The arrow points in the direction of strong X-Ray emission recorded in the graph below.

strong x-ray emission on surface of sun after the incident

Figure 6.20

This is a time sequence of SOHO-MDI images of the sun with sunspot labels. They were taken after the 7/20/2002 flare. What is the label of the Sunspot responsible for the July 20th event?

July 21
July 22
July 23
July 24
July 25
July 21, 2002
July 22, 2002
July 23, 2002
July 24, 2002
July 25, 2002


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