【CASK EFFECT】0910F阅读全方位锻炼--越障【SCI】 1-21

tuziduiduiUID：2599524

【CASK EFFECT】0910G阅读能力基础自测（速度、难度、深度、越障、真题、RAM）
https://bbs.gter.net/forum.php?mod=viewthread&tid=910464&highlight

【CASK EFFECT】0910F阅读全方位锻炼--越障【SCI】汇总贴
https://bbs.gter.net/thread-982020-1-1.html

规则：0 u, r. g$ C/ d+ [4 f5 C

我每天贴出1000字左右的一篇文字7 j) N0 Q, Q- ]( V4 E

没有别的要求，只要大家坚持读完就可以

如果你能坚持一个月，你会发现自己的阅读进化了~
[注]9 K7 C8 w4 {" L
1、直接在电脑屏幕面前做，虽然GRE阅读是在纸上考，但是这个过程会遏制你做笔记，同时给你的阅读造成视觉障碍，也就是把难度训练和抗干扰训练同步结合，增加效率（初期会很累，但是既然大家想要成为高手，那么就别对自己太温柔）

Today's Topic:The Latitudinal Effect of Corotating Interaction Regionson Galactic Cosmic Rays

1. Introduction
Galactic cosmic rays (GCRs) gyrating along open solar magnetic field lines are scattered by irregularities on these field lines with scale length comparable to the GCR gyroradius. This scattering inhibits GCRs from moving towards the inner heliosphere by forcing a random walkor slow diffusion process. Additional modulation mechanisms are the advective effect of the supersonic solar wind, which carries the frozen-inmagnetic field,the adiabatic cooling effect of the radial expansion of the wind, and the coherent influence of large-scale field gradient and curvature “drift” effects.

Observational studies have recently shown that the flux of GCRs could be largely regulated bythe evolution of the footprint location of open solar magnetic field lines (Cliverand Ling, 2001; Wang, Sheeley, and Rouillard, 2006;Rouillard, 2007). From our understanding of the solar corona and the evolution of open magnetic flux on the Sun (Wang, Hawley, and Sheeley, 1996;Fisk and Schwadron, 2001) it was suggested that the occurrence of isolated coronal holes(CHs), where these field lines are rooted during solar maximum, could be a controlling factor for shielding the inner heliosphere from GCRs (Wang,Sheeley, and Rouillard, 2006; Rouillard, 2007). These coronal holes give fast solar wind outflow and hence control the formation of corotating interaction regions (CIRs) at the interface of the fast streams and the slow solar wind.The evolution of CIRs is reasonably well understood following intensive analytical (Lee, 2001) and numerical work (Pizzo and Gosling, 1994).Their relevance to GCR shielding has been demonstrated observationally (Heberand Burger, 1999) and theoretically (Kóta and Jokipii, 1991; Kóta,1999, and references therein). The shock waves and compression regions(in which the interplanetary magnetic field is enhanced) ahead of CIRs are thought to be the main source of GCR modulation (Kóta, 1999). In the case of a single CIR, modulation models predict a rather limited effect and this is confirmed by observations of GCR decreases at Earth of only a few percent following transient passages of isolated CIRs. GCRs are thought to recover between two successive CIRs, in particular in the rarefied fast-flow regions behind the turbulent leading edge: The faster wind speed results in straighter field lines, which are likely to contain fewer fluctuations able to scatter GeV particles. The variation in the solar wind speed is substantially smaller than that in the magnetic field (which can change by an order of magnitude) so that diffusion effects from scattering by field irregularities are thought to predominate (Kóta, 1999).Particle drifts will be reduced by the enhanced turbulence within the CIRs but will be faster in the weak field between CIRs. Drift streamlines largely flow around CIRs; thus the global effect of an individual CIR remains limited beyond the region of compressed interplanetary magnetic field (IMF).

The study of solar-minimum GCR modulation produced by single CIRs is easier to carryout and provides very useful information for studying the propagation of energetic charged particles through the heliosphere, which is fundamental to gaining understanding of the 11-year modulation. We here present observation son the evolution of GCRs during the second half of the year 1996 near solar minimum when simultaneous observations were made of the solar photosphere and corona by the Solar and Heliospheric Observatory (SOHO)spacecraft, of the interplanetary medium at 1 AU by a combination of satellites(inter calibrated by the OMNI team), and of the flux of GCRs at Earth by a network of neutron monitors. Most studies of CIR/CME effects on galactic cosmic rays have compared GCR variations to solar wind speed features in the ecliptic(Morfill, Richter, and Scholer, 1979)and have not directly considered the latitudinal dimension of CIR/CME.

Firstly,we show that SOHO coronal images and solar magnetograms help provide a clear picture of the state of the solar corona between Carrington rotations (CRs)1912 to 1918. Secondly, we show that the most obvious coronal feature seen from Earth at that time is not responsible for the observed recurring galactic cosmic ray decreases. Thirdly, we use numerical modelling of the inner (<2.5Rs)and outer corona (>2.5Rs) to investigate the role of the morphology of CIRs on GCR shielding during this period. Using these three parts, we investigate the consequence of an isolated increase in the open solar flux with low-latitude footprints on GCRs.

The largest active region of a photospheric activity nest that lasted from May to November 1996 emerged in July (NOAA 7978) at latitude ψ =−10◦ and Carrington longitude φ = 259◦, while the Sun was near its minimum activity. This active region(identified subsequently as NOAA 07981 and NOAA 07986 in CRs 1912 and 1913,respectively) triggered the formation of extensions of both the northern and southern polar coronal holes. Wang et al. (1997a)described the evolution of the photospheric and lower coronal field from CRs1908 (starting 4 March) to 1913 (starting 22 August) using a potential field source surface (PFSS) extrapolation of the photospheric flux recorded by solar magnetographs.Wang et al. showed that the emergence of photospheric field during CR1911 led to the enhancement of the original field distribution and its associated equatorial dipole field, which led to the widening of the streamerbelt. The associated enhancement of the flux of open magnetic field lines located at low latitudes (<45◦) is shown in Figure 1b. This low-latitude open flux was quantified by using the PFSS method and consists of open field line footprints, which have no symmetric distribution relative to the solar rotation axis and are therefore part of the non-axisymmetric field (Wang, Sheeley, and Rouillard, 2006).Associated with this event, a series of large recurrent decreases were seen inthe flux of GCRs, measured by neutron monitors around the globe (Bromage,Browning, and Clegg, 2001). The data from the Climax neutron monitor are plotted in Figure 1a.Bromage, Browning, and Clegg showed that this recurrent variation occurredwhile there was a large extension of the northern polar CH, triggered by theemergence of the active region. Moreover, they showed that the source of themain recurrent GCR decrease could not have been forced by this northern polarcoronal hole extension; rather, it was forced by probable turbulence in thestreamer belt. Their analysis is re-examined here and carried further.

Mason.PDUID：2592013

我晕啊，这也到21啦，草木，找人把置顶帖更新下吧，我还以为自己速度很快呢。。。

dairymanUID：2683905

我觉得我阅读能力退步了……

lghscuUID：2552043

解决

bobo19890313UID：2622130

读过。。