Solar tsunami used to measure Sun’s magnetic field

Date:

Share post:

A solar tsunami observed by NASA’s Solar Dynamics Observatory (SDO) and the Japanese Hinode spacecraft has been used to provide the first accurate estimates of the Sun’s magnetic field.

Solar tsunami used to measure Sun’s magnetic field
An eruption on April 16, 2012 was captured here by NASA’s Solar Dynamics Observatory in the
304 Angstrom wavelength, which is typically colored in red [Credit: NASA/SDO/AIA]

Solar tsunamis are produced by enormous explosions in the Sun’s atmosphere called coronal mass ejections (CMEs). As the CME travels out into space, the tsunami travels across the Sun at speeds of up to 1000 kilometres per second.

Similar to tsunamis on Earth, the shape of solar tsunamis is changed by the environment through which they move. Just as sound travels faster in water than in air, solar tsunamis have a higher speed in regions of stronger magnetic field. This unique feature allowed the team, led by researchers from UCL’s Mullard Space Science Laboratory, to measure the Sun’s magnetic field. The results are outlined in a paper soon to be published in the journal Solar Physics.

Dr David Long, UCL Mullard Space Science Laboratory, and lead author of the research, said: “We’ve demonstrated that the Sun’s atmosphere has a magnetic field about ten times weaker than a normal fridge magnet.”

Using data obtained using the Extreme ultraviolet Imaging Spectrometer (EIS), a UK-led instrument on the Japanese Hinode spacecraft, the team measured the density of the solar atmosphere through which the tsunami was travelling.

The combination of imaging and spectral observations provides a rare opportunity to examine the magnetic field which permeates the Sun’s atmosphere.

Dr Long noted: “These are rare observations of a spectacular event that reveal some really interesting details about our nearest star.”

Visible as loops and other structures in the Sun’s atmosphere, the Sun’s magnetic field is difficult to measure directly and usually has to be estimated using intensive computer simulations. The Hinode spacecraft has three highly sensitive telescopes, which use visible, X-ray and ultraviolet light to examine both slow and rapid changes in the magnetic field.

The instruments on Hinode act like a microscope to track how the magnetic field around sunspots is generated, shapes itself, and then fades away. These results show just how sensitive these instruments can be, measuring magnetic fields that were previously thought too weak to detect.

The explosions that produce solar tsunamis can send CMEs hurtling towards the Earth. Although protected by its own magnetic field, the Earth is vulnerable to these solar storms as they can adversely affect satellites and technological infrastructure.

Dr Long said: “As our dependency on technology increases, understanding how these eruptions occur and travel will greatly assist in protecting against solar activity.”

Source: University College London [July 11, 2013]

ADVERTISEMENT

spot_img

Related articles

Statue of Amenhotep III found

A team of Egyptian and European archaeologists has unearthed a statue of the ancient Egyptian king Amenhotep III...

More on Neanderthals didn’t bite the volcanic dust

Invisible to the human eye, cryptotephra is a fine volcanic glass that is blasted out of erupting volcanoes...

The secret life of dodos, revealed

Has any animal suffered greater ignominy than the ill-fated dodo?  "A strange and grotesque specimen of bird... bearing...

Human-caused climate change a major factor in more frequent Mediterranean droughts

Wintertime droughts are increasingly common in the Mediterranean region, and human-caused climate change is partly responsible, according to...

Search for Europe’s oldest village concluded

Ever since humans built their first boat, offshore exploration has been one of the most fruitful ways to...

Revealing Cosmeston’s medieval past

A pottery vessel dating back to the 13th Century has been found by University archaeologists at Cosmeston, shedding...

Bogus archaeologists reported for stealing artifacts

The Antiquities Ministry of Egypt is pressing charges against three members of an alleged 'German archaeological mission' that...

Medusa to gaze once more from mosaic

She may no longer turn people into stone, but Medusa continues to arrest onlookers; now, even more people...