Moreton wave
Large-scale chromospheric perturbation
![](http://upload.wikimedia.org/wikipedia/en/f/f6/MoretonWaveAnimation200612.gif)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Solar_tsunami.jpg/200px-Solar_tsunami.jpg)
A Moreton wave , Solar Tsunami , or Moreton-Ramsey wave is the chromospheric signature of a large-scale solar corona shock wave . Described as a kind of solar " tsunami ", [1] they are generated by solar flares . They are named for American astronomer Gail Moreton , an observer at the Lockheed Solar Observatory in Burbank , and Harry E. Ramsey , an observer who spotted them in 1959 at The Sacramento Peak Observatory. [2] [3] [4] He discovered them in time-lapse photography of the chromosphere in the light of the Balmer alpha transition .
There were few follow-up studies for decades. Then the 1995 launch of the Solar and Heliospheric Observatory (SOHO) led to observation of coronal waves, which cause Moreton waves. Moreton waves were a research topic again. (SOHO's EIT instrument discovered another, different wave type called "EIT waves".) [5] The reality of Moreton waves (also known as fast-mode MHD waves) has also been confirmed by the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. They observed a 100,000-km-high wave of hot plasma and magnetism, moving at 250 km/s, in conjunction with a big coronal mass ejection in February 2009. [6] [7] Moreton measured the waves propagating at a speed of 500–1500 km/s. [6] Yutaka Uchida interpreted Moreton waves as MHD fast mode shock waves propagating in the corona. [8] He links them to type II radio bursts, which are radio-wave discharges created when coronal mass ejections accelerate shocks. [9]
Moreton waves can be observed primarily in the Hα band. [10]
See also
References
- ↑ Phillips, Tony (November 24, 2009). "Monster Waves on the Sun are Real" . NASA . Retrieved 16 July 2010 .
- ↑ Moreton, G. E. (1960). "Hα Observations of Flare-Initiated Disturbances with Velocities ~1000 km/sec". Astronomical Journal . 65 : 494. Bibcode : 1960AJ.....65U.494M . doi : 10.1086/108346 .
- ↑ Moreton, G. E. & Ramsey, H. E. (1960). "Recent Observations of Dynamical Phenomena Associated with Solar Flares" . Publications of the Astronomical Society of the Pacific . 72 (428): 357. Bibcode : 1960PASP...72..357M . doi : 10.1086/127549 .
- ↑ Athay, R. Grant; Moreton, Gail E. (1961). "Impulsive Phenomena of the Solar Atmosphere. I. Some Optical Events Associated with Flares Showing Explosive Phase" . Astrophysical Journal . 133 : 935. Bibcode : 1961ApJ...133..935A . doi : 10.1086/147098 .
- ↑ Thompson, B.; Plunkett, S. P.; Gurman, J. B.; Newmark, J.S.; St. Cyr, O.C.; Michels, D.J. (1998). "SOHO/EIT observations of an Earth-directed coronal mass ejection on May 12, 1997" . Geophysical Research Letters . 25 (14): 2465–2468. Bibcode : 1998GeoRL..25.2465T . doi : 10.1029/98GL50429 . S2CID 120367644 .
- 1 2 Atkins, William (26 November 2009). "STEREO spacecraft finds gigantic tsunami on Sun" . iTWire . Retrieved 16 July 2010 .
- ↑ JPL/NASA (19 November 2009). "Mystery of the Solar Tsunami -- Solved" . PhysOrg.com . Retrieved 16 July 2010 .
- ↑ Sakurai, Takashi (3 September 2002). "SolarNews Newsletter" . Solar Physics Division, American Astronomical Society. Archived from the original on 27 August 2011 . Retrieved 15 June 2011 .
- ↑ Layton, Laura (May 15, 2009). "STEREO Spies First Major Activity of Solar Cycle 24" . NASA . Retrieved 15 June 2011 .
- ↑ Narukage, N.; Eto, Shigeru; Kadota, Miwako; Kitai, Reizaburo; Kurokawa, Hiroki; Shibata, Kazunari (2004). "Moreton waves observed at Hida Observatory" . Proceedings IAU Symposium . 2004 (223): 367–370. Bibcode : 2004IAUS..223..367N . doi : 10.1017/S1743921304006143 .
- More of Moreton's papers can be found here (SAO/NASA System) .
External links
- "Have you ever heard the Sun?" - many recordings (MP3 format) of solar radio emissions including a solar flare shockfront.