Slow EIT waves as gravity modes

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Authors
Vranjes, J.
Discipline
Physical sciences
Subject
Extreme-ultraviolet imaging telescopes
Gravity modes
Low speed
Low-propagation
Propagation velocities
Solar and heliospheric observatories
Sound speed
Theory of gravity
Transverse mode
Wave models
Wave speed
Magnetoacoustic effects
Speed
Diagnostic radiography
Audience
Scientific
Date
2011Metadata
Show full item recordDescription
The EIT waves named after the extreme-ultraviolet imaging telescope (EIT) onboard the solar and heliospheric observatory (SOHO) are in the literature usually described as fast magneto-acoustic (FMA) modes. However, observations show that a large percentage of these events propagate with very slow speeds that may be as low as 20 km/s. This is far below the FMA wave speed which cannot be below the sound speed, the latter being typically larger than 10 2 km/s in the corona. In the present study, it is shown that, to account for such low propagation speed, a different wave model should be used, based on the theory of gravity waves, both internal (IG) and surface (SG) ones. The gravity modes are physically completely different from the FMA mode, as they are essentially dispersive and in addition the IG wave is a transverse mode. Both the IG and the SG mode separately can provide proper propagation velocities in the whole low speed range.
Citation
Vranjes, J. (2011). Slow EIT waves as gravity modes. , Physics of Plasmas, Vol. 18, Issue 6, 62902, DOI: 10.1063/1.3597136.Identifiers
scopus: 2-s2.0-79960170031
Type
Article
Peer-Review
Yes
Language
eng