Miyake et al. (henceforth M12) recently reported, based on 14C data, an extreme cosmic event ca. AD775. Using a simple model, M12 claimed that the event was too strong to be caused by a solar flare within the standard theory. This implied a new paradigm of either an impossibly strong solar flare or a very strong cosmic ray event of unknown origin occurred ca. AD775. We show that the strength of the event was significantly overestimated by M12. Several subsequent works have attempted to find a possible exotic source for such an event, but they are all based on incorrect estimates by M12. We revisit this event with analysis of new datasets and consistent theoretical modelling. We verified the experimental result for the AD775 event using independent datasets including 10Be series and newly measured 14C annual data. We surveyed available historical chronicles for astronomical observations for the AD770s to identify potential sightings of aurorae or supernovae. We interpreted the 14C measurements using an appropriate carbon cycle model. We show that: (1) The reality of the AD775 event is confirmed by new measurements of 14C; (2) by using an inappropriate carbon cycle model, M12 strongly overestimated the event's strength; (3) The revised magnitude of the event is consistent with different independent datasets (14C, 10Be, 36Cl) and can be associated with a strong, but not inexplicably strong, SEP event (or a sequence of events), and provides the first evidence for an event of this magnitude (the fluence >30 MeV was about 4.5*10^{10} /cm2) in multiple datasets; (4) This is in agreement with increased auroral activity identified in historical chronicles. This point to the likely solar origin of the event, which is the greatest solar event on a multi-millennial time scale, placing a strong observational constraint on the theory of explosive energy releases on the Sun and cool stars.
Magnetized jets driven by the sun: the structure of the heliosphere revisited
日光层的经典观点是一个静止的彗星状形状，沿着太阳穿过星际介质（ISM）的方向延伸1000个天文单位（AU：天文单位）。在这里，我们表明，磁流体动力学（MHD）模拟的基础上，扭曲的磁场的太阳的张力（箍）力限制的太阳风等离子体以外的终止冲击和驱动器的喷流到北方和南方非常像天体物理喷流。这些喷流被太阳通过ISM的运动偏转到尾部区域，类似于弯曲的星系喷流穿过星系际介质。星际风将两股喷流吹向尾部，但不足以迫使两瓣形成一个彗星状的尾部，就像一些天体物理喷流一样（Morsony et al. 2013）。相反，星际风绕着日光层流动，进入两个喷流之间的赤道区域。正如在一些扭结不稳定的天体物理喷流中一样（Porth等人，2014），我们在这里表明，日光层喷流是湍流的（由于大尺度MHD不稳定性和重联），并且强烈地混合了太阳风与400 AU以上的ISM。由此产生的湍流对日光层中的粒子加速具有重要意义。两瓣结构与IBEX（McComas等人，2013年）的日尾高能中性原子（ENA）图像一致，其中在北部和南部可以看到两个瓣，以及CASSINI（Krimigis等人，2009年，Dialynas等人，2013年）ENA的建议，即日光层是“无尾的”。
Ion-Scale Solitary Structures in the Solar Wind Observed by Solar Orbiter and Parker Solar Probe
Imperial College London（帝国理工学院）；European Space Agency, European Space Astronomy Centre（欧洲空间局，欧洲空间天文中心）；Institut de Recherche en Astrophysique et Planétologie, CNRS, Université de Toulouse, CNES（天体物理与行星学研究所在，法国国家科学研究中心，图卢兹大学，法国国家空间研究中心）；Space Sciences Laboratory, University of California, Berkeley（加州大学伯克利分校，空间科学实验室）；Physics Department, University of California, Berkeley（加州大学伯克利分校，物理系）；Harvard-Smithsonian Center for Astrophysics（哈佛-史密松天体物理中心）；LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université（巴黎天文台，PSL大学，索邦大学，巴黎西岱大学，CY塞吉-巴黎大学）；Swedish Institute of Space Physics（瑞典空间物理研究所）；Department of Physics and Astronomy, Uppsala University（乌普萨拉大学，物理与天文系）；Istituto per la Scienza e la Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche（意大利国家研究委员会，等离子体科学与技术研究所）
Response to "Comment on `Resolving the 180deg Ambiguity in Solar Vector Magnetic Field Data: Evaluating the Effects of Noise, Spatial Resolution, and Method Assumptions'"
