用Metis日冕仪对外日冕太阳风的首次观测
太阳与恒星天体物理
2021-06-28 v1
摘要
对太阳日冕中太阳风的研究始于利用UVCS-SOHO获得的日冕等离子体共振散射紫外发射的观测，该仪器旨在通过多普勒变暗诊断测量风外流速度。太阳轨道器上的Metis补充了在太阳活动第23周期间进行的UVCS光谱观测，通过同时成像偏振可见光和HI Ly-alpha日冕，以获得连续膨胀的太阳大气向外速度的高空间和时间分辨率图。Metis在2020年5月15日的观测提供了扩展日冕的首批HI Ly-alpha图像，以及太阳活动极小期期间日冕等离子体外流速度的首次瞬时图，并使我们能够识别观测到慢风的层。利用Metis两个通道获得的偏振可见光（580-640 nm）和紫外HI Ly-alpha（121.6 nm）日冕发射，将它们结合以测量相对于静态日冕的紫外发射变暗。该效应由日冕等离子体沿色球光子入射日冕中性氢方向的外向运动引起。然后根据测得的多普勒变暗导出等离子体外流速度。静态日冕紫外发射是基于由偏振可见光推断的等离子体电子密度模拟的。本研究在太阳日冕速度图中识别出约±10度宽的高密度层，该层以位于东边缘的宁静赤道流光延伸为中心，此处最慢的风从4 Rs到6 Rs处以约（160 ± 18）km/s流动。在高密度层边界之外，风速迅速增加，标志着日冕中慢风与快风之间的过渡。
引用
@article{arxiv.2106.13344,
title = {First light observations of the solar wind in the outer corona with the Metis coronagraph},
author = {M. Romoli and E. Antonucci and V. Andretta and G. E. Capuano and V. Da Deppo and Y. De Leo and C. Downs and S. Fineschi and P. Heinzel and F. Landini and A. Liberatore and G. Naletto and G. Nicolini and M. Pancrazzi and C. Sasso and D. Spadaro and R. Susino and D. Telloni and L. Teriaca and M. Uslenghi and Y. M. Wang and A. Bemporad and G. Capobianco and M. Casti and M. Fabi and F. Frassati and F. Frassetto and S. Giordano and C. Grimani and G. Jerse and E. Magli and G. Massone and M. Messerotti and D. Moses and M. G. Pelizzo and P. Romano and U. Schühle and A. Slemer and M. Stangalini and T. Straus and C. A. Volpicelli and L. Zangrilli and P. Zuppella and L. Abbo and F. Auchére and R. Aznar Cuadrado and A. Berlicki and R. Bruno and A. Ciaravella and R. D'Amicis and P. Lamy and A. Lanzafame and A. M. Malvezzi and P. Nicolosi and G. Nisticò and H. Peter and C. Plainaki and L. Poletto and F. Reale and S. K. Solanki and L. Strachan and G. Tondello and K. Tsinganos and M. Velli and R. Ventura and J. C. Vial and J. Woch and G. Zimbardo},
journal= {arXiv preprint arXiv:2106.13344},
year = {2021}
}