%0 Generic %1 citeulike:13993510 %A Cho, Jungyeon %A Yoo, Hyunju %D 2016 %K imported %T A technique for constraining the driving scale of turbulence and a modified Chandrasekhar-Fermi method %U http://arxiv.org/abs/1603.08537 %X The Chandrasekhar-Fermi method is a powerful technique for estimating the strength of the mean magnetic field projected on the plane of the sky. In this paper, we present a technique for improving the Chandrasekhar-Fermi method, in which we take into account the averaging effect arising from independent eddies along the line of sight . In the conventional Chandrasekhar-Fermi method, the strength of fluctuating magnetic field divided by \$4 \bar\rho\$, where \$\rho\$ is average density, is assumed to be comparable to the line-of-sight velocity dispersion. This however is not true when the driving scale of turbulence \$L\_f\$, i.e. the outer scale of turbulence, is smaller than the size of the system along the line of sight \$L\_los\$. In fact, the conventional Chandrasekhar-Fermi method over-estimates the strength of the mean plane-of-the-sky magnetic field by a factor of \$ L\_los/L\_f\$. We show that the standard deviation of centroid velocities divided by the average line-of-sight velocity dispersion is a good measure of \$ L\_los/L\_f\$, which enables us to propose a modified Chandrasekhar-Fermi method.

@misc{citeulike:13993510, abstract = {The Chandrasekhar-Fermi method is a powerful technique for estimating the strength of the mean magnetic field projected on the plane of the sky. In this paper, we present a technique for improving the Chandrasekhar-Fermi method, in which we take into account the averaging effect arising from independent eddies along the line of sight . In the conventional Chandrasekhar-Fermi method, the strength of fluctuating magnetic field divided by \$\sqrt{4 \pi \bar{\rho}}\$, where \$\bar{\rho}\$ is average density, is assumed to be comparable to the line-of-sight velocity dispersion. This however is not true when the driving scale of turbulence \$L\_f\$, i.e. the outer scale of turbulence, is smaller than the size of the system along the line of sight \$L\_{los}\$. In fact, the conventional Chandrasekhar-Fermi method over-estimates the strength of the mean plane-of-the-sky magnetic field by a factor of \$\sim \sqrt{ L\_{los}/L\_f}\$. We show that the standard deviation of centroid velocities divided by the average line-of-sight velocity dispersion is a good measure of \$\sqrt{ L\_{los}/L\_f}\$, which enables us to propose a modified Chandrasekhar-Fermi method.}, added-at = {2019-03-25T08:20:55.000+0100}, archiveprefix = {arXiv}, author = {Cho, Jungyeon and Yoo, Hyunju}, biburl = {https://www.bibsonomy.org/bibtex/2e43b64f1bde69407a75babea9e6389b8/ericblackman}, citeulike-article-id = {13993510}, citeulike-linkout-0 = {http://arxiv.org/abs/1603.08537}, citeulike-linkout-1 = {http://arxiv.org/pdf/1603.08537}, day = 28, eprint = {1603.08537}, interhash = {21d67eea3f9ccb32eba5cc0f7459d14a}, intrahash = {e43b64f1bde69407a75babea9e6389b8}, keywords = {imported}, month = mar, posted-at = {2016-04-02 21:22:10}, priority = {2}, timestamp = {2019-03-25T08:20:55.000+0100}, title = {{A technique for constraining the driving scale of turbulence and a modified Chandrasekhar-Fermi method}}, url = {http://arxiv.org/abs/1603.08537}, year = 2016 }