Signatures of Alfvén‐cyclotron wave‐ion scattering: Advanced Composition Explorer (ACE) solar wind observations
Signatures of Alfvén‐cyclotron wave‐ion scattering: Advanced Composition Explorer (ACE) solar wind observations
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DOI：
10.1029/2004ja010569
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发表时间：
2005-07
影响因子：
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通讯作者：
S. Gary;Charles W. Smith;R. Skoug
中科院分区：
文献类型：
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作者：
S. Gary;Charles W. Smith;R. Skoug
[1]理论和模拟预测，在无碰撞等离子体中，波长足够短且与背景磁场Bo近似平行或反平行传播的Alfven回旋涨落会散射离子，从而增加离子在垂直于Bo方向的能量。由电子、质子和α粒子组成的均匀、各向同性等离子体的线性Vlasov理论预测，α粒子的回旋共振特性和这种涨落的离子回旋衰减是α/质子相对速度的敏感函数。如果强烈的离子共振对应于强烈的离子俯仰角散射，线性理论意味着太阳风α和质子的各向异性中有可观察到的特征。报道了利用先进成分探测器(ACE)航天器上的等离子体和磁场仪器在接近1AU的太阳风中测量到的质子和α粒子各向异性的统计分析，这些分析与这些特征基本一致。
[1] Theory and simulations predict that Alfven-cyclotron fluctuations of sufficiently short wavelengths and at propagation approximately parallel or antiparallel to the background magnetic field B o in collisionless plasmas scatter ions so as to increase their energies in the directions perpendicular to B o . Linear Vlasov theory for a homogeneous, isotropic plasma of electrons, protons, and alpha particles predicts that alpha particle cyclotron resonance properties and ion cyclotron damping of such fluctuations are sensitive functions of the alpha/proton relative velocity. If a strong ion resonance corresponds to strong ion pitch-angle scattering, linear theory implies observable signatures in the anisotropies of solar wind alphas and protons. Statistical analyses of proton and alpha particle anisotropies measured in the solar wind near 1 AU by the plasma and magnetic field instruments on the Advanced Composition Explorer (ACE) spacecraft are reported which are largely consistent with such signatures.