Supra-arcade downflows (SADs) have been observed with Yohkoh/SXT (soft X-rays (SXR)), TRACE (extreme ultra-violet (EUV)), SoHO/LASCO (white light), SoHO/SUMER (EUV spectra), and Hinode/XRT (SXR). Characteristics such as low emissivity and trajectories which slow as they reach the top of the arcade are consistent with post-reconnection magnetic flux tubes retracting from a reconnection site high in the corona until they reach a lower-energy magnetic configuration. Viewed from a perpendicular angle, SADs should appear as shrinking loops rather than downflowing voids. We present XRT observations of supra-arcade downflowing loops (SADLs) following a coronal mass ejection (CME) on 2008 April 9 and show that their speeds and decelerations are consistent with those determined for SADs. We also present evidence for a possible current sheet observed during this flare that extends between the flare arcade and the CME. Additionally, we show a correlation between reconnection outflows observed with XRT and outgoing flows observed with LASCO.
Comparison of Hinode/XRT and RHESSI detection of hot plasma in the non-flaring solar corona
我们比较了观测的非耀斑太阳日冕同时与Hinode/XRT和RHESSI。2006年11月12日分析的日冕主要由一个单一的活动区。对排放措施进行了比较。我们推导出发射测量分布与温度的整个活动区从多滤波器XRT数据。我们检查的兼容性与总排放量的测量值估计的流量与RHESSI测量,如果排放来自等温等离子体。我们发现,RHESSI和XRT数据分析一致指向存在一个次要的排放测量组件峰值在log T ~ 6.8-6.9。XRT和RHESSI结果之间的差异在几个因素之内,表明交叉一致性的可接受水平。
Evidence of widespread hot plasma in a non-flaring coronal active region from Hinode/XRT
纳米耀斑,在空间上无法分辨的磁链中的短而强的热脉冲,现在被认为是解决日冕加热问题的主要候选者。然而,频繁出现的纳米耀斑要求耀斑热等离子体始终存在于日冕中。到目前为止,它的探测被证明是难以捉摸的,部分原因是预测的强度非常微弱。在这里,我们报告的一个活跃的区域观察到的5个过滤器的日之出/XRT在2006年11月的分析。我们已经使用的过滤器比率的方法来获得软,硬比率的温度和排放量的地图。这些图是近似的,因为等离子体被假设为沿着每个视线是等温的。尽管如此,最难的可用比率揭示了约10 MK的血浆的明显存在。为了获得更详细的等离子体特性的信息,我们进行了蒙特卡罗模拟假设各种非等温发射测量分布沿视线。我们发现,所观察到的过滤器的比率意味着双峰分布组成的一个强冷(log T ~ 6.3-6.5)的组件和较弱(百分之几)和较热(6.6 < log T < 7.2)的组件。数据与沿所有视线的双峰分布一致,即,整个活跃区域。我们还发现,从过滤器的比率推断的等温温度敏感地依赖于冷组件的精确温度。该分量的轻微偏移可能导致热分量在硬比率测量中被遮蔽。因此,以硬比率和软比率制作的温度图往往是反相关的。我们的结论是,这一观察结果支持存在广泛的nanoflaring活动的活跃区域。
We have reviewed the first year of observations of the Solar X-ray Monitor (XSM) onboard Chandrayaan-2, and the available multi-wavelength observations to complement the XSM data, focusing on Solar Dynamics Observatory AIA and Hinode XRT, EIS observations. XSM has provided disk-integrated solar spectra in the 1--15 keV energy range, observing a large number of microflares. We present an analysis of multi-wavelength observations of AR 12759 during its disk crossing. We use a new radiometric calibration of EIS to find that the quiescent AR core emission during its disk crossing has a distributio…
One of the key processes associated with the "standard" flare model is chromospheric evaporation, a process where plasma heated to high temperatures by energy deposition at the flare footpoints is driven upwards into the corona. Despite several decades of study, a number of open questions remain, including the relationship between plasma produced during this process and observations of earlier "superhot" plasma. Hinode/EIS has a wide slot often used as a flare trigger in the He II emission line band. Once the intensity passes a threshold level, the study switches to one focussed on the flaring…
We examine in greater detail five events previously identified as being sources of strong transient coronal outflows in a solar polar region in Hinode/EUV Imaging Spectrometer (EIS) Doppler data. Although relatively compact or faint and inconspicuous in Hinode/Soft X-ray Telescope (XRT) soft-X-ray (SXR) images and in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) EUV images, we find that all of these events are consistent with being faint coronal X-ray jets. The evidence for this is that the events result from eruption of minifilaments of projected sizes spanning 5000 -- 1…
During transient events such as major solar eruptions, the plasma can be far from the equilibrium ionization state because of rapid heating or cooling. Non-equilibrium ionization~(NEI) is important in rapidly evolving systems where the thermodynamical timescale is shorter than the ionization or recombination time scales. We investigate the effects of NEI on EUV and X-ray observations by the Atmospheric Imaging Assembly (AIA) on board Solar Dynamic Observatory and X-ray Telescope (XRT) on board Hinode. Our model assumes that the plasma is initially in ionization equilibrium at low temperature, …
Direct Observations of Magnetic Reconnection Outflow and CME Triggering in a Small Erupting Solar Prominence
我们研究了2014年5月1日01:35 UT发生的一次小日珥喷发,并由太阳动力学天文台(SDO)的界面区成像光谱仪(IRIS)和大气成像组件(AIA)观测到。爆发前和爆发后的图像是由日之上的X射线望远镜(XRT)拍摄的。在爆发前,日珥上方存在一个圆顶状的结构,以日冕雨为分界。随着喷发的进行,我们发现了日珥磁场和上覆磁场重连的证据。在AIA和IRIS中可以看到快速流动,表明重新连接流出。在AIA 171 A通道中,沿一条可能重新连接的磁力线观测到了~300 km s $^{-1}$的天平面流。IRIS探测到与AIA气流一致的、约200 km s $^{-1}$的间歇性快速视线气流。差分排放测量计算表明,加热的快速流动的起源。喷发后的XRT图像显示,热环可能是由于重新配置的磁场在喷发和随后的加热等离子体在这些环路。虽然有证据表明在爆发期间日珥上方的重连,但IRIS的高空间分辨率图像显示了日珥下方的潜在重连地点。对爆发日珥的高度-时间分析表明,日珥的初始上升速度为~0.4 km/s $^{-1}$,随后迅速加速,最终速度为~250 km/s $^{-1}$。在这两个阶段之间的过渡期间,IRIS的亮度表明,爆发的快速部分的爆发触发器可能是一个系绳切割机制,而不是突破机制。
In this multi-instrument paper, we search for evidence of sustained magnetic reconnection far beyond the impulsive phase of the X8.2-class solar flare on 2017 September 10. Using Hinode/EIS, CoMP, SDO/AIA, K-Cor, Hinode/XRT, RHESSI, and IRIS, we study the late-stage evolution of the flare dynamics and topology, comparing signatures of reconnection with those expected from the standard solar flare model. Examining previously unpublished EIS data, we present the evolution of non-thermal velocity and temperature within the famous plasma sheet structure, for the first four hours of the flare's dur…
Context. We present an analysis of a GOES M1.8 flare with excellent observational coverage in UV, EUV, and X-ray, including observations from the instruments IRIS, SDO with AIA, Hinode/EIS, Hinode/XRT, and Solar Orbiter with the Spectrometer/Telescope for Imaging X-rays (STIX). Hard X-ray emission is often observed at the footpoints of flare loops and is occasionally observed in the corona. In this flare, four nonthermal hard X-ray sources are seen. Aim. Our aim is to understand why we can observe four individual nonthermal sources in this flare and how we can characterize the physical propert…