Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry, CV4 7AL, United Kingdom.
Phys Rev Lett. 2012 Jun 29;108(26):261102. doi: 10.1103/PhysRevLett.108.261102. Epub 2012 Jun 26.
Evidence for nonuniform heating in the solar wind plasma near current sheets dynamically generated by magnetohydrodynamic (MHD) turbulence is obtained using measurements from the ACE spacecraft. These coherent structures only constitute 19% of the data, but contribute 50% of the total plasma internal energy. Intermittent heating manifests as elevations in proton temperature near current sheets, resulting in regional heating and temperature enhancements extending over several hours. The number density of non-Gaussian structures is found to be proportional to the mean proton temperature and solar wind speed. These results suggest magnetofluid turbulence drives intermittent dissipation through a hierarchy of coherent structures, which collectively could be a significant source of coronal and solar wind heating.
使用 ACE 航天器的测量结果,获得了在磁流体力学(MHD)湍流动态产生的电流片中太阳风等离子体非均匀加热的证据。这些相干结构仅占数据的 19%,但贡献了总等离子体内能的 50%。间歇性加热表现为电流片附近质子温度升高,导致区域加热和温度升高持续数小时。非高斯结构的数密度被发现与平均质子温度和太阳风速度成正比。这些结果表明磁流体力学湍流通过一系列相干结构驱动间歇性耗散,这些结构集体可能是日冕和太阳风加热的重要来源。