标题： 质子尺度磁涨落的光谱特征：从快速到慢速太阳风 显示英文标题

标题： Spectral Features of Magnetic Fluctuations at Proton Scales from Fast to Slow Solar Wind

摘要： 这封信研究了在快速流速度剖面中选择的几个时间段内，质子尺度行星际磁场波动的光谱特性。 在第一个频率十年内的波动特征，超出流体和动力学区域之间的高频断裂点，强烈依赖于风的类型。 虽然快速风显示出右旋和左旋极化波动的明显特征，可能分别与KAW和离子回旋波有关，而风速和低频波动的阿尔芬性下降的稀疏区域则显示出离子回旋特征的迅速消失，随后是KAWs的更渐进的消失。 此外，与垂直和平行波动相关的功率也经历了迅速的耗减，但保持了有利于垂直谱的功率各向异性。 显示英文摘要

摘要： This Letter investigates the spectral characteristics of the interplanetary magnetic field fluctuations at proton scales during several time intervals chosen along the speed profile of a fast stream. The character of the fluctuations within the first frequency decade, beyond the high frequency break located between the fluid and the kinetic regime, strongly depends on the type of wind. While the fast wind shows a clear signature of both right handed and left handed polarized fluctuations, possibly associated with KAW and Ion-Cyclotron waves, respectively, the rarefaction region, where the wind speed and the Alfv\'{e}nicity of low frequency fluctuations decrease, shows a rapid disappearance of the ion-cyclotron signature followed by a more gradual disappearance of the KAWs. Moreover, also the power associated to perpendicular and parallel fluctuations experiences a rapid depletion, keeping, however, the power anisotropy in favour of the perpendicular spectrum.