Presented here is a review of present knowledge of the long-term behavior of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method. The concept of solar activity is discussed along with an overview of the special indices used to quantify different aspects of variable solar activity, with special emphasis upon sunspot number.Over long timescales, quantitative information about past solar activity can only be obtained using a method based upon indirect proxies, such as the cosmogenic isotopes ¹⁴C and ¹⁰Be in natural stratified archives (e.g., tree rings or ice cores). We give an historical overview of the development of the proxy-based method for past solar-activity reconstruction over millennia, as well as a description of the modern state. Special attention is paid to the verification and cross-calibration of reconstructions. It is argued that this method of cosmogenic isotopes makes a solid basis for studies of solar variability in the past on a long timescale (centuries to millennia) during the Holocene.A separate section is devoted to reconstructions of strong solar energetic-particle (SEP) events in the past, that suggest that the present-day average SEP flux is broadly consistent with estimates on longer timescales, and that the occurrence of extra-strong events is unlikely.Finally, the main features of the long-term evolution of solar magnetic activity, including the statistics of grand minima and maxima occurrence, are summarized and their possible implications, especially for solar/stellar dynamo theory, are discussed.

中文翻译：

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几千年来太阳活动的历史

这里介绍的是对使用间接代理方法重建的太阳活动在几千年时间尺度上的长期行为的当前知识的回顾。讨论了太阳活动的概念，并概述了用于量化可变太阳活动的不同方面的特殊指标，特别是太阳黑子数。在很长的时间范围内，只能使用基于间接代表，例如宇宙同位素¹⁴ C和¹⁰存放在自然的分层档案中（例如，年轮或冰芯）。我们对过去几千年来过去的太阳活动重建基于代理的方法的发展进行了历史综述，并描述了现代状态。特别注意重建的验证和交叉校准。有人认为，这种宇宙成因同位素方法为全新世长期以来（几百年到几千年）太阳活动的研究奠定了坚实的基础。一个单独的部分专门研究了强太阳高能粒子（SEP）的重建过去的事件表明，目前的平均SEP通量与较长时间范围内的估计值大致一致，并且不太可能发生强事件。