Helioviewer.org - Solar and heliospheric image visualization tool Solar Tsunami Rips Across the Sun Two solar observatories have joined forces to witness a rare phenomenon: a solar tsunami. Immediately after an eruption of a coronal mass ejection in the lower corona (the sun’s multimillion degree atmosphere), observations by NASA’s Solar Dynamics Observatory (SDO) and Japan’s Hinode solar observatory tracked a vast wave blast across the upper plasma layers of the sun. By doing so, scientists were able to accurately measure the strength of the sun’s magnetic field and test a method that may ultimately help space weather forecasters predict the characteristics of coronal mass ejections (CMEs). PHOTOS: Simmering Solar Views from SDO This particular tsunami — technically known as an “EIT wave” after the EIT instrument on board the veteran NASA/ESA Solar and Heliospheric Observatory (SoHO) that made their discovery — was clocked speeding at up to 1,000 kilometers (620 miles) per second through the highly magnetized, searingly hot solar plasma. ANALYSIS: There’s a Hole in the Sun!
Sound of the Sun LIVE SOUND OF THE SUN.flv Sleepy sun thickens the slow solar wind - space - 10 January 2014 Even the sun needs a break. A slowdown in solar activity has given us the first real clue about a period of dramatic solar behaviour 350 years ago. In 2008, the sun entered a deep lull in magnetic activity. Spacecraft measurements show that this caused a belt of sluggish particles, known as the slow solar wind, to thicken. Produced near the sun's equator, the belt is normally narrow and ruched like a ballerina's tutu. Because Earth orbits at a 14 degree tilt relative to the sun's equator, it passes in and out of these ruches during the year. To find out how severe such slowdowns might be, Mike Lockwood and Matt Owens at the University of Reading, UK, used the 2008 measurements to model the belt's thickness during the most extreme solar minimum on record: the Maunder Minimum. Not so windy The model showed that the solar wind speed probably dropped to just 250 to 275 kilometres a second during this period. But don't expect another mini ice age, says Lockwood. More From New Scientist
On The Day The Solar Wind Disappeared, Scientists Sample Particles Directly From The Sun On The Day The Solar Wind Disappeared, Scientists Sample Particles Directly From The Sun Courtesy NASA (December 13, 1999) From May 10-12, 1999, the solar wind that blows constantly from the Sun virtually disappeared -- the most drastic and longest-lasting decrease ever observed. Dropping to a fraction of its normal density and to half its normal speed, the solar wind died down enough to allow physicists to observe particles flowing directly from the Sun's corona to Earth. This severe change in the solar wind also changed the shape of Earth's magnetic field and produced an unusual auroral display at the North Pole. Starting late on May 10 and continuing through the early hours of May 12, NASA's ACE and Wind spacecraft each observed that the density of the solar wind dropped by more than 98%. "This event provides a window to see the Sun's corona directly," said Dr. "Normally, our view of the corona from Earth is like seeing the Sun on an overcast, cloudy day," said Dr. Images & Animations