Using Dendrograms to Determine Sonic and Alfvén Mach number in MHD Turbulence

Type Conference Paper
Names Blakesley K. Burkhart
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #216, #424.01
Volume 41
Pages 836
Date May 1, 2010
Library Catalog NASA ADS
Abstract We used hierarchical tree diagrams known as dendrograms to characterize isothermal MHD turbulence with a wide variety of compressibility and magnetization. We find that the distribution of local maxima of emission have statistical dependencies on sonic and Alfvén Mach numbers. In particular we see a rather strong dependence on Alfvén Mach number with mean and variance of the dendrogram especially for the cases were we also have a large sonic Mach number. Two methods for looking at dendrograms are explored which are defined in respect to the one parameter (delta) of the dendrogram which sets the definition of local maximum. Method 1 holds delta constant for all data while Method 2 varies delta and looks at deviations in the distributions Gaussian asymmetry. Concerning Method 2, we find that higher order moments are also dependent on compressibility and magnetization and, when the tree diagram is well sampled, are generally independent of spacial resolution. Both methods should be used in order to get fully reliable measures of turbulence parameters from the dendrogram. BB is funded by the NSF Graduate Research Fellowship
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