Solar physicists failed to predict the exact shape of the Sun鈥檚 corona during Thursday鈥檚 total eclipse over southern Africa.
On Tuesday, Zoran Mikic and colleagues from the Space Applications International Corporation (SAIC) in San Diego published a computer model prediction. This was based on measurements of the Sun鈥檚 magnetic field strength.
But Jim Klimchuk, who studies the solar corona at the Naval Research Laboratory in Washington DC, says the match is not particularly good. 鈥淚t wasn鈥檛 as nice as one would hope.鈥�
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The SAIC team did face a difficult task. The Sun is at the peak of the its 11-year activity cycle and is rapidly evolving and erupting. 鈥淚t wasn鈥檛 really their fault,鈥� says Klimchuk.
Mikic says he is looking forward to examining higher resolution images of the eclipse next week in order to see how well his prediction for the structure of the outer coronal fields matches. 鈥淚t鈥檚 hard to tell from these images,鈥� he says.
The poor match is a setback for the SAIC team and for space weather forecasters who are seeking a more accurate model of the Sun鈥檚 magnetic behaviour.
But Klimchuk remains upbeat about the quality of Mikic鈥檚 model and says forecasters are in dire need of better and more up-to-date magnetic data to work with.
Klimchuk鈥檚 own prediction, that there was a good chance the Sun would release a coronal mass ejection (CME) during the eclipse, was fulfilled. CMEs are 100,000 kilometre-long ejections of material that can lead to magnetic storms when directed at Earth.
During the eclipse, a bright white prominence was clearly visible, probably the heart of a CME.
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