Effects of supra-arcade downflows interacting with the post-flare arcade

Supra-arcade downflows (SADs) are dark voids descending through plasma above the post-flare arcade. Although they are generally viewed as byproducts of flare reconnections in the corona, the nature of SADs is under debate. Here we investigated six distinct episodes of SADs observed in the post-maximum phase of an M-class flare of April 11, 2013. Differential emission measure analysis revealed that SAD cases occurring close to the flare maximum contain an enhanced hot plasma component at 5--7~MK whereas those occurring later exhibited a depression in hot plasma at 7--12~MK compared to the ambient supra-arcade plasma. On-disk location of the flare enabled us to examine in detail the interaction of SADs with the post-flare arcade, whose effects include 1) transverse oscillations of period $\sim\,$160~s in the supra-arcade rays in the wake of voids, 2) footpoint brightening in 1700{~\AA} whose peak is delayed by 22-46~s with respect to the SAD's arrival at the top of the arcade, and 3) EUV intensity perturbations expanding and propagating with a speed $\sim\,$400 km~s$^{-1}$. On the other hand, due to line-of-sight confusion in the optically thin corona, the ribbon enhancement following the interaction produces an illusion of plasma rebound at the top of the arcade, where the interaction fails to yield significant plasma heating. These effects indicate that the interaction mainly generates MHD waves propagating toward the surface, which may further produce quasi-periodic brightening at flare ribbons, therefore contributing to quasi-periodic flare gradual phase emission in EUV.Comment: Accepted for publication in the Astrophysical Journal, Animation files - 4 (Refer to the published version

Acceleration and Expansion of a Coronal Mass Ejection in the High Corona: Role of Magnetic Reconnection

The important role played by magnetic reconnection in the early acceleration of coronal mass ejections (CMEs) has been widely discussed. However, as CMEs may have expansion speeds comparable to their propagation speeds in the corona, it is not clear whether and how reconnection contributes to the true acceleration and expansion separately. To address this question, we analyze the dynamics of a moderately fast CME on 2013 February 27, associated with a continuous acceleration of its front into the high corona, even though its speed had reached $\sim$700~km~s$^{-1}$ and larger than the solar wind speed. The apparent CME acceleration is found to be due to the CME expansion in the radial direction. The CME true acceleration, i.e., the acceleration of its center, is then estimated by taking into account the expected deceleration caused by the solar wind drag force acting on a fast CME. It is found that the true acceleration and the radial expansion have similar magnitudes. We find that magnetic reconnection occurs after the CME eruption and continues during the CME propagation in the high corona, which contributes to the CME dynamic evolution. Comparison between the apparent acceleration related to the expansion and the true acceleration that compensates the drag shows that, for this case, magnetic reconnection contributes almost equally to the CME expansion and to the CME acceleration. The consequences of these measurements for the evolution of CMEs as they transit from the corona to the heliosphere are discussed.Comment: Accepted by Ap

Correlation between dietary patterns and cognitive function in older Chinese adults: A representative cross-sectional study

ObjectiveThe objective of this study was to investigate the relationship between dietary patterns and cognitive function in older adults (≥60 years old).MethodsFood intake was quantitatively assessed by the Food Frequency Questionnaire (FFQ), and cognitive function was assessed by the Chinese version of the Simple Mental State Examination Scale (MMSE). Four major dietary patterns were identified by the factor analysis (FA) method. The relationship between dietary patterns and cognitive function was evaluated by logistic regression.ResultsA total of 884 participants were included in the study. Four dietary patterns (vegetable and mushroom, oil and salt, seafood and alcohol, and oil tea dietary patterns) were extracted. In the total population, Model III results showed that the fourth quartile of dietary pattern factor scores for the vegetable and mushroom pattern was 0.399 and 7.056. The vegetable and mushroom dietary pattern may be a protective factor for cognitive function, with p-value = 0.033, OR (95% CI): 0.578 (0.348, 0.951) in Model III (adjusted for covariates: sex, ethnic, marital, agricultural activities, smoking, drinking, hypertension, diabetes, dyslipidemia, BMI, and dietary fiber). In the ethnic stratification analysis, the scores of dietary pattern factors of the vegetable and mushroom among the Yao participants were 0.333 and 5.064. The Vegetable and mushroom diet pattern may be a protective factor for cognitive function, p-value = 0.012, OR (95% CI): 0.415 (0.206, 0.815).ConclusionThe fourth quartile of the vegetable and mushroom dietary pattern scores showed dose-dependent and a strong correlation with cognitive function. Currently, increasing vegetable and mushroom intake may be one of the effective ways to prevent and mitigate cognitive decline. It is recommended to increase the dietary intake of vegetables and mushroom foods

Solar Ring Mission: Building a Panorama of the Sun and Inner-heliosphere

Solar Ring (SOR) is a proposed space science mission to monitor and study the Sun and inner heliosphere from a full 360{\deg} perspective in the ecliptic plane. It will deploy three 120{\deg}-separated spacecraft on the 1-AU orbit. The first spacecraft, S1, locates 30{\deg} upstream of the Earth, the second, S2, 90{\deg} downstream, and the third, S3, completes the configuration. This design with necessary science instruments, e.g., the Doppler-velocity and vector magnetic field imager, wide-angle coronagraph, and in-situ instruments, will allow us to establish many unprecedented capabilities: (1) provide simultaneous Doppler-velocity observations of the whole solar surface to understand the deep interior, (2) provide vector magnetograms of the whole photosphere - the inner boundary of the solar atmosphere and heliosphere, (3) provide the information of the whole lifetime evolution of solar featured structures, and (4) provide the whole view of solar transients and space weather in the inner heliosphere. With these capabilities, Solar Ring mission aims to address outstanding questions about the origin of solar cycle, the origin of solar eruptions and the origin of extreme space weather events. The successful accomplishment of the mission will construct a panorama of the Sun and inner-heliosphere, and therefore advance our understanding of the star and the space environment that holds our life.Comment: 41 pages, 6 figures, 1 table, to be published in Advances in Space Researc