This figure shows the composition of a large event which was measured by ACE-SWICS on May 3 and compares it to standard solar wind composition (labelled slow solar wind). The Fe and O charge state show that the CME plasma is composed of a very hot (about 2.5-3 million K) and a very cold (less than 0.3 million K) component.
Click on image for full size
Image courtesy of ACE-SWICS
ACE Satellite Probes Solar Event
News story originally written on June 8, 1998
During the last months, there have been more Coronal Mass Ejections
(CMEs) than usual. In fact, one such event was recorded just last week by SOHO. Another CME
was recorded by the ACE spacecraft
on May 3. The ACE satellite measurements
show something very unusual about these CMEs.
These explosion events were first discovered in the 1970's. Since they were discovered not too long ago, scientists are still finding out about these CMEs. The ACE satellite found that the CME that passed it last month wasn't made up of material that is all the same temperature. Instead, it was found that the CME was made of an extremely hot region, followed by a cooler region and then another hot region of solar material. This discovery could change what scientists know about CMEs and about how CMEs affect the Earth's environment.
CMEs can definitely affect Earth. They can cause strong geomagnetic storms, aurorae or electrical power blackouts. So we need to know when these CMEs are coming. That is why we have spacecraft like ACE. The ACE satellite serves as a spaceweather station while in orbit. ACE can provide about one-hour advance warning of any major geomagnetic storms.
As we near solar maximum, more and more CMEs are likely to occur.
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