Microturbulence

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Microturbulence is a form of turbulence that varies over small distance scales. (Large-scale turbulence is called macroturbulence.)

Contents 1 Stellar 2 Magnetic nuclear fusion 3 Oceanography 4 References 5 External links

[edit] Stellar

In the chromosphere of a star, microturbulence can be caused by turbulence in the outer atmosphere. It is one of several mechanisms that can cause broadening of the absorption lines in the stellar spectrum.^[1] Stellar microturbulence varies with the effective temperature and the surface gravity.^[2]

The plasma in a star undergoes convection as a mechanism for energy transport. When examined by a spectroscope, the velocity of the convective gas along the line of sight produces Doppler shifts in the absorption bands. It is the distribution of these velocities along the line of sight that produces the microturbulence broadening of the absorption lines. The strength of the microturbulence (symbolized by ξ, in units of km s^-1) can be determined by comparing the broadening of strong lines versus weak lines.^[3]

[edit] Magnetic nuclear fusion

Microturbulence also plays a critical role in energy transport during magnetic nuclear fusion experiments, such as the Tokamak.^[4]

[edit] Oceanography

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[edit] References

1. ^ De Jager, C. (1954). "High-energy Microturbulence in the Solar Photosphere". Nature 173: 680–1. doi:10.1038/173680b0. 
2. ^ Montalban, J.; Nendwich, J.; Heiter, U.; Kupka, F.; Paunzen, E.; Smalley, B. (1999). "The Effect of the microturbulence parameter on the Color-Magnitude Diagram". Reports on Progress in Physics 61: 77–115. doi:10.1088/0034-4885/61/2/001. 
3. ^ Briley, Michael (July 13, 2006). Stellar Properties from Spectral Lines: Introduction. University of Wisconsin. Retrieved on 2007-05-21.
4. ^ Nevins, W.M. (August 21, 2006). The Plasma Microturbulence Project. Lawrence Livermore National Laboratory. Retrieved on 2007-05-21.

[edit] External links

• Landstreet, J. D. (August 21-25, 2006). "Observing Atmospheric Convection in Stars". Symposium no. 239 - Convection in Astrophysics, Prague, Czech Republic: International Astronomical Union. Retrieved on 2007-05-21.