Flickering loops of plasma above the Sun’s churning surface have been captured in movies made by Japan’s Hinode spacecraft, providing a preview of what the probe will do once it begins its main phase of scientific observations.
The spacecraft, formerly called Solar-B, was launched by the Japan Aerospace Exploration Agency on 22 September 2006 (see Spacecraft launches to study Sun’s magnetic field). JAXA is collaborating with NASA, ESA, and other organisations for the mission.
Hinode’s three telescopes will make simultaneous observations in visible light, ultraviolet, and X-rays to help scientists understand the Sun’s ever-changing magnetic field. It is hoped that its observations will shed light on what triggers solar eruptions – called coronal mass ejections (CMEs). These ejections spew out radiation that poses a health risk for astronauts and they can also knock out satellites.
One video, made with Hinode’s optical telescope, shows the development of loops of hot plasma above the Sun’s surface (mpeg format). The loops form when especially hot plasma rises from the surface and moves along the Sun’s curved magnetic field lines. In some cases the gas quickly cools again and falls back down to the surface.
Mission team member John Davis, at NASA’s Marshall Space Flight Center in Huntsville, Alabama, US, says the heating that injects plasma into the loops is thought to come from a sudden release of energy stored in the magnetic field – events called magnetic reconnections.
“One of the things that we’re trying to do is to understand reconnection and heating processes and how that energy gets released,” he told New Scientist. Magnetic reconnection events on a larger scale may be the cause of CMEs, Davis says.
Another video, also made using the optical telescope, shows activity around a sunspot. Two bright streaks that suddenly appear towards the end of the video at the lower left probably represent a plasma loop, but one for which only its two ends anchored to the surface are visible, Davis says.
The mission team is still testing out the spacecraft’s instruments, but full scientific observations will probably be underway by January 2007, Davis says.
By continuously recording the Sun’s activity, the project scientists hope to better understand the conditions that set off dangerous solar eruptions. “We will try to look and see when the big flares and CMEs go off and then we will look at the magnetic field structure prior to that and see if there’s any signature” which could be used to predict eruptions, Davis says.