Observational features of equatorial coronal hole jets
G. Nistico', V. Bothmer, S. Patsourakos, G. Zimbardo
备注：
9 pages, 8 figures, 1 table, accepted for publication in Annales Geophysicae, Special Issue:'Three eyes on the Sun-multi-spacecraft studies of the corona and impacts on the heliosphere'
Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet events are selected by requiring at least some visibility in both COR1 and EUVI instruments. We report 15 jet events, and we discuss their main features. For one event, the uplift velocity has been determined as about 200 km/s, while the deceleration rate appears to be about 0.11 km/s2, less than solar gravity. The average jet visibility time is about 30 minutes, consistent with jet observed in polar regions. On the basis of the present dataset, we provisionally conclude that there are not substantial physical differences between polar and equatorial coronal hole jets.
Spectroscopic diagnostics of solar coronal plasmas critically depends on the uncertainty in the measured line intensities. One of the main sources of uncertainty is instrumental scattered light, which is potentially most important in low-brightness areas. In the solar corona, such areas include polar and equatorial coronal holes, which are the source regions of the solar wind; instrument-scattered light must thus pose a significant obstacle to studies of the source regions of the solar wind. In this paper we investigate the importance of instrument-scattered light on observations of equatorial…
We use full-disk, SOHO/EIT 195 $Å$ calibrated images to measure latitudinal and day to day variations of area and average photon fluxes of the near equatorial coronal holes. In addition, energy emitted by the coronal holes with their temperature and strength of magnetic field structures are estimated. By analyzing data of 2001-2008, we find that variations of average area (A), photon flux (F), radiative energy (E) and temperature (T) of coronal holes are independent of latitude. Whereas inferred strength of magnetic field structure of the coronal holes is dependent on the latitudes and varies …
Because of its distinctive compositional properties and variability, low-speed ($\lesssim 450$ km s$^{-1}$) solar wind is widely believed to originate from coronal streamers, unlike high-speed wind, which comes from coronal holes. An alternative scenario is that the bulk of the slow wind (excluding that in the immediate vicinity of the heliospheric current sheet) originates from rapidly diverging flux tubes rooted inside small coronal holes or just within the boundaries of large holes. This viewpoint is based largely on photospheric field extrapolations, which are subject to considerable uncer…
Small, impulsive jets commonly occur throughout the solar corona, but are especially visible in coronal holes. Evidence is mounting that jets are part of a continuum of eruptions that extends to much larger coronal mass ejections and eruptive flares. Because coronal-hole jets originate in relatively simple magnetic structures, they offer an ideal testbed for theories of energy buildup and release in the full range of solar eruptions. We analyzed an equatorial coronal-hole jet observed by SDO/AIA on 09 January 2014, in which the magnetic-field structure was consistent with the embedded-bipole t…
Axial-Dipole and Equatorial-Dipole Coronal Holes: Congruent Magnetic Geometry, Divergent Evolution
Advanced Heliophysics Inc.（高级日球物理公司）；US Naval Research Laboratory（美国海军研究实验室）；Center for Astrophysics, Harvard & Smithsonian（哈佛-史密森天体物理中心）；European Space Agency, ESTEC（欧洲空间局，欧洲空间研究与技术中心）
Dynamic features, such as chromospheric jets, transition region network jets, coronal plumes and coronal jets, are abundant in the network regions of the solar polar coronal holes. We investigate the relationship between chromospheric jets and coronal activities (e.g., coronal plumes and jets).We analyze observations of a polar coronal hole including the filtergrams that were taken by the New Vacuum Solar Telescope (NVST) at the Hα-0.6 Åto study the Hα jets,and the Atmospheric Imaging Assembly (AIA) 171 Å images to follow the evolution of coronal activities. Hα jets are persistent in the netwo…
Observations from the X-ray telescope (XRT) on Hinode are used to study the nature of X-ray bright points, sources of coronal jets. Several jet events in the coronal holes are found to erupt from small-scale, S-shaped bright regions. This finding suggests that coronal micro-sigmoids may well be progenitors of coronal jets. Moreover, the presence of these structures may explain numerous observed characteristics of jets such as helical structures, apparent transverse motions, and shapes. In analogy to large-scale sigmoids giving rise to coronal mass ejections (CMEs), a promising future task woul…
Observations from the Hinode X-ray telescope (XRT) are used to study the structure of X-ray bright points (XBPs), sources of coronal jets. Several jet events are found to erupt from S-shaped bright points, suggesting that coronal micro-sigmoids are progenitors of the jets. The observations may help to explain numerous characteristics of coronal jets, such as helical structures and shapes. They also suggest that solar activity may be self-similar within a wide range of scales in terms of both properties and evolution of the observed coronal structures.
Jets (transient/collimated plasma ejections) occur frequently throughout the solar corona and contribute mass/energy to the corona and solar wind. By combining numerical simulations and high-resolution observations, we have made substantial progress recently on determining the energy buildup and release processes in these jets. Here we describe a study of 27 equatorial coronal-hole jets using Solar Dynamics Observatory/AIA and HMI observations on 2013 June 27-28 and 2014 January 8-10. Out of 27 jets, 18 (67%) are associated with mini-filament ejections; the other 9 (33%) do not show mini-filam…
Using EUV images and line-of-sight magnetograms from Solar Dynamics Observatory, we examine eight emerging bipolar magnetic regions (BMRs) in central-disk coronal holes for whether the emerging magnetic arch made any noticeable coronal jets directly, via reconnection with ambient open field as modeled by Yokoyama and Shibata (1995). During emergence, each BMR produced no obvious EUV coronal jet of normal brightness, but each produced one or more faint EUV coronal jets that are discernible in AIA 193 Å images. The spires of these jets are much fainter and usually narrower than for typical EUV j…
Solar coronal jets have been observed in detail since the early 1990s. While it is clear that these jets are magnetically driven, the details of the driving process has recently been updated. Previously it was suspected that the jets were a consequence of magnetic flux emergence interacting with ambient coronal field. New evidence however indicates that often the direct driver of the jets is erupting field, often carrying cool material (a "minifilament"), that undergoes interchange magnetic reconnection with preexisting field ([1]). More recent work indicates that the trigger for eruption of t…
Coronal Jets are transitory small-scale eruptions omnipresent in solar observations. Active regions jets produce significant perturbations on the ambient solar atmosphere and are believed to be generated by microflare reconnection. Multiple sets of recurrent jets are identified in extreme-ultraviolet filter imaging. In this work we analyze the long time-scale recurrence of coronal jets originating from a unique footpoint structure observed in the lower corona. We report the detection of penumbral magnetic structures in the lower corona. These structures, that we entitled "Coronal Geysers", per…
Coronal jets are transient narrow features in the solar corona that originate from all regions of the solar disk: active regions, quiet sun, and coronal holes. Recent studies indicate that at least some coronal jets in quiet regions and coronal holes are driven by the eruption of a minifilament following flux cancellation at a magnetic neutral line. We have tested the veracity of that view by examining 60 random jets in quiet regions and coronal holes using multithermal (304 A, 171 A, 193 A, and 211 A) extreme ultraviolet (EUV) images from the Solar Dynamics Observatory (SDO)/Atmospheric Imagi…
We investigate the effect of coronal temperature on the formation process of solar chromospheric jets using two-dimensional magnetohydrodynamic simulations of the region from the upper convection zone to the lower corona. We develop a new radiative magnetohydrodynamic code for the dynamic modeling of the solar atmosphere, employing a LTE equation of state, optically thick radiative loss in the photosphere, optically thin radiative loss in the chromosphere and the corona, and thermal conduction along the magnetic field lines. Many chromospheric jets are produced in the simulations by shock wave…
We investigate in detail the magnetic cause of minifilament eruptions that drive coronal-hole jets. We study 13 random on-disk coronal hole jet eruptions, using high resolution X-ray images from Hinode/XRT, EUV images from SDO/AIA, and magnetograms from SDO/HMI. For all 13 events, we track the evolution of the jet-base region and find that a minifilament of cool (transition-region-temperature) plasma is present prior to each jet eruption. HMI magnetograms show that the minifilaments reside along a magnetic neutral line between majority-polarity and minority-polarity magnetic flux patches. Thes…
Ulysses data obtained at high solar latitudes during periods of minimum solar activity in 1994 and 2007 are examined to determine the relation between velocity structures called microstreams and folds in the magnetic field called switchbacks. A high correlation is found. The possibility of velocity peaks in microstreams originating from coronal X-ray jets is re-examined; we now suggest that microstreams are the consequence of the alternation of patches of switchbacks and quiet periods, where the switchbacks could be generated by minifilament/flux rope eruptions that cause coronal jets.
We suggest that clumpy-dense outflowing equatorial rings around evolved giant stars, such as in supernova 1987A and the Necklace planetary nebula, are formed by bipolar jets that compress gas toward the equatorial plane. The jets are launched from an accretion disk around a stellar companion. Using the FLASH hydrodynamics numerical code we perform 3D numerical simulations, and show that bipolar jets expanding into a dense spherical shell can compress gas toward the equatorial plane and lead to the formation of an expanding equatorial ring. Rayleigh-Taylor instabilities in the interaction regio…
"EIT waves" are freely-propagating global pulses in the low corona which are strongly associated with the initial evolution of coronal mass ejections (CMEs). They are thought to be large-amplitude, fast-mode magnetohydrodynamic waves initially driven by the rapid expansion of a CME in the low corona. An "EIT wave" was observed on 6 July 2012 to impact an adjacent trans-equatorial loop system which then exhibited a decaying oscillation as it returned to rest. Observations of the loop oscillations were used to estimate the magnetic field strength of the loop system by studying the decaying oscil…
Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy content of the corona and solar wind, but the extent of these contributions remains uncertain. We have recently modeled the formation and evolution of coronal jets using a three-dimensional (3D) magnetohydrodynamic (MHD) code with thermodynamics in a large spherical domain that includes the solar wind. Our model is coupled to 3D MHD flux-emergence simulatio…
Recent IRIS observations have revealed a prevalence of intermittent small-scale jets with apparent speeds of 80 - 250 km s$^{-1}$, emanating from small-scale bright regions inside network boundaries of coronal holes. We find that these network jets appear not only in coronal holes but also in quiet-sun regions. Using IRIS 1330A (C II) slit-jaw images, we extract several parameters of these network jets, e.g. apparent speed, length, lifetime and increase in foot-point brightness. Using several observations, we find that some properties of the jets are very similar but others are obviously diffe…
We investigate intensity oscillations observed simultaneously in the quiet chromosphere and in the corona, above an enhanced network area at the boundary of an equatorial coronal hole. A Fourier analysis is applied to a sequence of images observed in the 171 A and 1600 A passbands of TRACE. Four interesting features above the magnetic network are further investigated by using a wavelet analysis. Our results reveal that, in both the 171 A and 1600 A passbands, oscillations above the magnetic network show a lack of power at high frequencies (5.0-8.3 mHz), and a significant power at low (1.3-2.0 …
Coronal jets are collimated, dynamic events that occur over a broad range of spatial scales in the solar corona. In the open magnetic field of coronal holes, jets form quasi-radial spires that can extend far out into the heliosphere, while in closed-field regions the jet outflows are confined to the corona. We explore the application of the embedded-bipole model to jets occurring in closed coronal loops. In this model, magnetic free energy is injected slowly by footpoint motions that introduce twist within the closed dome of the jet source region, and is released rapidly by the onset of an ide…
Both coronal plumes and network jets are rooted in network lanes. The relationship between the two, however, has yet to be addressed. For this purpose, we perform an observational analysis using images acquired with the Atmospheric Imaging Assembly (AIA) 171Å passband to follow the evolution of coronal plumes, the observations taken by the Interface Region Imaging Spectrograph (IRIS) slit-jaw 1330Å to study the network jets, and the line-of-sight magnetograms taken by the Helioseismic and Magnetic Imager (HMI) to overview the the photospheric magnetic features in the regions. Four regions in t…
We report high-resolution, high-cadence observations of five small-scale coronal jets in an on-disk quiet Sun region observed with Solar Orbiter's EUI/\hri\ in 174 Å. We combine the \hri\ images with the EUV images of SDO/AIA and investigate magnetic setting of the jets using co-aligned line-of-sight magnetograms from SDO/HMI. The \hri\ jets are miniature versions of typical coronal jets as they show narrow collimated spires with a base brightening. Three out of five jets result from a detectable minifilament eruption following flux cancelation at the neutral line under the minifilament, analo…
A new solar feature termed a dark jet is identified from observations of an extended solar coronal hole that was continuously monitored for over 44 hours by the EUV Imaging Spectrometer on board the Hinode spacecraft in 2011 February 8-10. Line-of-sight velocity maps derived from the coronal Fe XII $λ$195.12 emission line, formed at 1.5 MK, revealed a number of large-scale, jet-like structures that showed significant blueshifts. The structures had either weak or no intensity signal in 193 A filter images from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, suggesting …
Coronal jets, which extend from the solar surface to beyond 2 $R_\odot$, were observed in the polar coronal hole regions during the total solar eclipse on 2017 August 21. In a time-series of white-light images of the corona spanning 70 minutes taken with our multi-site observations of this eclipse, six jets were found as narrow structures upwardly ejected with the apparent speed of about 450 km s$^{-1}$ in polar plumes. On the other hand, extreme-ultraviolet (EUV) images taken with the Atmospheric Image Assembly of the Solar Dynamics Observatory show that all of the eclipse jets were preceded …
We study a series of X-ray-bright, rapidly-evolving active-region coronal jets outside the leading sunspot of AR 12259, using Hinode/XRT, SDO/AIA and HMI, and IRIS data. The detailed evolution of such rapidly evolving "violent" jets remained a mystery after our previous investigation of active region jets (Sterling et al. 2016, Paper 1). The jets we investigate here erupt from three localized subregions, each containing a rapidly evolving (positive) minority-polarity magnetic-flux patch bathed in a (majority) negative-polarity magnetic-flux background. At least several of the jets begin with e…
We study 14 large solar jets observed in polar coronal holes. In EUV movies from SDO/AIA, each jet appears similar to most X-ray jets and EUV jets that erupt in coronal holes, but each is exceptional in that it goes higher than most, so high that it is observed in the outer corona beyond 2.2 RSun in images from the SOHO/LASCO/C2 coronagraph. From AIA He II 304 Å movies and LASCO/C2 running-difference images of these high-reaching jets, we find: (1) the front of the jet transits the corona below 2.2 RSun at a speed typically several times the sound speed; (2) each jet displays an exceptionally …
Recent observations have revealed that many solar coronal jets involve the eruption of miniature versions of large-scale filaments. Such "mini-filaments" are observed to form along the polarity inversion lines of strong, magnetically bipolar regions embedded in open (or distantly closing) unipolar field. During the generation of the jet, the filament becomes unstable and erupts. Recently we described a model for these mini-filament jets, in which the well-known magnetic-breakout mechanism for large-scale coronal mass ejections is extended to these smaller events. In this work we use three-dime…
We present the sympathetic eruption of a standard and a blowout coronal jets originating from two adjacent coronal bright points (CBP1 and CBP2) in a polar coronal hole, using soft X-ray and extreme ultraviolet observations respectively taken by the Hinode and the Solar Dynamic Observatory. In the event, a collimated jet with obvious westward lateral motion firstly launched from CBP1, during which a small bright point appeared around CBP1's east end, and magnetic flux cancellation was observed within the eruption source region. Based on these characteristics, we interpret the observed jet as a…
Coronal jets and bright points occur prolifically in predominantly unipolar magnetic regions, such as coronal holes, where they appear above minority-polarity intrusions. Intermittent low-level reconnection and explosive, high-energy-release reconnection above these intrusions are thought to generate bright points and jets, respectively. The magnetic field above the intrusions possesses a spine-fan topology with a coronal null point. The movement of magnetic flux by surface convection adds free energy to this field, forming current sheets and inducing reconnection. We conducted three-dimension…
Coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of significant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of "nominal" solar flares and coronal mass ejections (CMEs), jets share many common properties with these phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spe…
Coronal-hole jets occur ubiquitously in solar coronal holes, at EUV and X-ray bright points associated with intrusions of minority magnetic polarity. The embedded-bipole model for these jets posits that they are driven by explosive, fast reconnection between the stressed closed field of the embedded bipole and the open field of the surrounding coronal hole. Previous numerical studies in Cartesian geometry, assuming uniform ambient magnetic field and plasma while neglecting gravity and solar wind, demonstrated that the model is robust and can produce jet-like events in simple configurations. We…
The detailed observational analysis of a homologous Extreme-ultraviolet (EUV) wave event is presented to study the driving mechanism and the physical property of the EUV waves, combining high resolution data taken by the Solar Dynamics Observatory and the Solar TErrestrial RElations Observatory. It is observed that four homologous EUV waves originated from the same active region AR11476 within about one hour, and the time separations between consecutive waves were of 8 - 20 minutes. The waves showed narrow arc-shaped wavefronts and propagated in the same direction along a large-scale transequa…
We utilize observations from {\emph{Hinode}}/XRT and the Extreme ultraviolet (EUV) imagers onboard {\emph{STEREO}} to study the relationship between coronal jets and plumes. The data were recorded on Apr. 7-8 and Nov. 2-4, 2007. Detailed results are presented for the Apr. campaign along with preliminary analysis of the Nov. observations. We find that $>90%$ of the identified jets are directly related to plumes (Apr. data). EUV data show that plume haze rose from the same spatial location of more than 70% of the identified jets. The remaining jets occurred in areas where plume material exists a…
We present the first observation, analysis and modeling of solar coronal twin jets, which occurred after a preceding jet. Detailed analysis on the kinetics of the preceding jet reveals its blowout-jet nature, which resembles the one studied in Liu et al. 2014. However the erupting process and kinetics of the twin jets appear to be different from the preceding one. In lack of the detailed information on the magnetic fields in the twin jet region, we instead use a numerical simulation using a three-dimensional (3D) MHD model as described in Fang et al. 2014, and find that in the simulation a pai…
We examine a sampling of 23 polar-coronal-hole jets. We first identified the jets in soft X-ray (SXR) images from the X-ray telescope (XRT) on the Hinode spacecraft, over 2014-2016. During this period, frequently the polar holes were small or largely obscured by foreground coronal haze, often making jets difficult to see. We selected 23 jets among those adequately visible during this period, and examined them further using Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) 171, 193, 211, and 304 Ang images. In SXRs we track the lateral drift of the jet spire relative to the je…
We investigate the acceleration source of the impulsive solar energetic particle (SEP) events on 2007 January 24. Combining the in situ electron measurements and remote-sensing solar observations, as well as the calculated magnetic fields obtained from a potential-field source-surface model, we demonstrate that the jets associated with the hard X-ray flares and type-III radio bursts, rather than the slow and partial coronal mass ejections, are closely related to the production of interplanetary electron streams. The jets, originated from the well-connected active region (AR 10939) whose magnet…
Solar jets are fast-moving, elongated brightenings related to ejections seen in both images and spectra on all scales from barely visible chromospheric jets to coronal jets extending up to a few solar radii. The largest, most powerful jets are the source of type III radio bursts, energetic electrons and ions with greatly enhanced $^3$He and heavy element abundances. The frequent coronal jets from polar and equatorial coronal holes may contribute to the solar wind. The primary acceleration mechanism for all jets is believed to be release of magnetic stress via reconnection; however the energy b…
Coronal Bright Points (CBPs) are ubiquitous structures in the solar atmosphere composed of hot small-scale loops observed in EUV or X-Rays in the quiet Sun and coronal holes. They are key elements to understand the heating of the corona; nonetheless, basic questions regarding their heating mechanisms, the chromosphere underneath, or the effects of flux emergence in these structures remain open. We have used the Bifrost code to carry out a 2D experiment in which a coronal-hole magnetic nullpoint configuration evolves perturbed by realistic granulation. To compare with observations, synthetic SD…
In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008. The appearances of the coronal jets were always correlated with underlying small-scale chromospheric bright points. A basic characterisation of the morphology and identification of the presence of helical structure were established with respect to recently proposed mode…
In this paper, we report our multiwavelength observations of subarcsecond blobs in coronal jets. In AR 12149, a C5.5 circular-ribbon flare occurred on 2014 August 24. Two jets (jet1 and jet2) were related to the flare. Jet1 appeared first. Jet2 appeared 6 minutes later. During its initial phase, a big plasmoid was ejected out of jet2. After the flare peak time, multiple bright and compact blobs appeared in the lower part of jet2, which were observed by IRIS/SJI. The blobs observed by SJI in 1330 Å have sizes of 0$\farcs$45$-$1$\farcs$35, nearly 84\% of which are subarcsecond ($<$1\arcsec). The…
We examine 21 solar polar coronal jets that we identify in soft X-ray images obtained from the Hinode/X-ray telescope (XRT). We identify 11 of these jets as blowout jets and four as standard jets (with six uncertain), based on their X-ray-spire widths being respectively wide or narrow (compared to the jet's base) in the XRT images. From corresponding Extreme Ultraviolet (EUV) images from the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA), essentially all (at least 20 of 21) of the jets are made by minifilament eruptions, consistent with other recent studies. Here, we exa…
High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. We found observational evidence that supports the idea that polar jets are very likely pr…
Solar X-ray jets are evidently made by a burst of reconnection of closed magnetic field in a jet's base with ambient "open" field (1,2). In the widely-accepted version of the "emerging-flux" model, that reconnection occurs at a current sheet between the open field and emerging closed field and also makes a compact hot brightening that is usually observed at the edge of the jet's base (1,3). Here we report on high-resolution X-ray and EUV observations of 20 randomly-selected X-ray jets in polar coronal holes. In each jet, contrary to the emerging-flux model, a miniature version of the filament …
Observations of reconnection jets in the solar corona are emerging as a possible diagnostic to study highly elusive coronal heating. Such nanojets can be observed in coronal loops and they have been linked to nanoflares. However, while models successfully describe the bilateral post-reconnection magnetic slingshot effect that leads to the jets, observations reveal that nanojets are unidirectional, or highly asymmetric, with only the jet travelling inward with respect to the coronal loop's curvature being clearly observed. The aim of this work is to address the role of the curvature of the coro…
Recent observations show that the buildup and triggering of minifilament eruptions that drive coronal jets result from magnetic flux cancelation at the neutral line between merging majority- and minority-polarity magnetic flux patches. We investigate the magnetic setting of ten on-disk small-scale UV/EUV jets (jetlets), smaller than coronal X-ray jets but larger than chromospheric spicules) in a coronal hole by using IRIS UV images and SDOAIA EUV images and line-of-sight magnetograms from SDO/HMI. We observe recurring jetlets at the edges of magnetic network flux lanes in the coronal hole. Fro…
In this paper,we report a detailed analysis of recurrent jets originated from a location with emerging, canceling and converging negative magnetic field at the east edge of NOAA active region AR11166 from 2011 March 09 to 10. The event presented several interesting features. First, a satellite sunspot appeared and collided with a pre-existing opposite polarity magnetic field and caused a recurrent solar jet event. Second, the evolution of the jets showed blowout-like nature and standard characteristics. Third, the satellite sunspot exhibited a motion toward southeast of AR11166 and merged with…
In this paper, we carry out multiwavelength observations of three recurring jets on 2014 November 7. The jets originated from the same region at the edge of AR 12205 and propagated along the same coronal loop. The eruptions were generated by magnetic reconnection, which is evidenced by continuous magnetic cancellation at the jet base. The projected initial velocity of the jet2 is 402 km s. The accelerations in the ascending and descending phases of jet2 are not consistent, the former is considerably larger than the value of solar gravitational acceleration at the solar surface, while the latte…
We report observations of ten random on-disk solar quiet region coronal jets found in high resolution Extreme Ultraviolet (EUV) images from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and having good coverage in magnetograms from the SDO/Helioseismic and Magnetic Imager (HMI). Recent studies show that coronal jets are driven by the eruption of a small-scale filament (called a minifilament). However the trigger of these eruptions is still unknown. In the present study we address the question: what leads to the jet-driving minifilament eruptions? The EUV observations …
Coronal jets are transient, collimated eruptions that occur in regions of predominantly open magnetic field in the solar corona. Our understanding of these events has greatly evolved in recent years but several open questions, such as the contribution of coronal jets to the solar wind, remain. Here we present an overview of the observations and numerical modeling of coronal jets, followed by a brief description of "next-generation" simulations that include an advanced description of the energy transfer in the corona ("thermodynamic MHD"), large spherical computational domains, and the solar wi…
Indian Institute of Astrophysics（印度天体物理研究所）；Pondicherry University（本地治里大学）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Rosseland Centre for Solar Physics, University of Oslo（奥斯陆大学罗斯兰太阳物理中心）；Institute of Theoretical Astrophysics, University of Oslo（奥斯陆大学理论天体物理研究所）
We present a multi-wavelength analysis of two flare-related jets on November 13, 2014, using data from SDO/AIA, RHESSI, Hinode/XRT, and IRIS. Unlike most coronal jets where hard X-ray (HXR) emissions are usually observed near the jet base, in these events HXR emissions are found at several locations, including in the corona. We carry out the first differential emission measure (DEM) analysis that combines both AIA (and XRT when available) bandpass filter data and RHESSI HXR measurements for coronal jets, and obtain self-consistent results across a wide temperature range and into non-thermal en…
Successive Coronal Jets as Novel Facilitators for Filament Oscillation and Eruption
School of Physics and Astronomy, Yunnan University（云南大学物理与天文学院）；Yunnan Key Laboratory of the Solar physics and Space Science（云南省太阳物理与空间科学重点实验室）；School of Intelligence Science and Technology, Nanjing University（南京大学智能科学与技术学院）
Coronal bright points (CBPs) and jets are ubiquitous small-scale brightenings that are often associated with each other. In this paper, we report our multiwavelength observations of two groups of homologous jets. The first group was observed by the EUVI aboard the behind STEREO spacecraft in 171 Å and 304 Å on 2014 September 10, from a location where data from the SDO could not observe. The jets (J1$-$J6) recurred for six times with intervals of 5$-$15 minutes. They originated from the same primary CBP (BP1) and propagated in the northeast direction along large-scale, closed coronal loops. Two…
We report observations of homologous coronal jets and their coronal mass ejections (CMEs) observed by instruments onboard the Solar Dynamics Observatory (SDO) and Solar and Heliospheric Observatory (SOHO) spacecraft. The homologous jets originated from a location with emerging and canceling magnetic field at the southeast edge of the giant active region (AR) of 2014 October, NOAA 12192. This AR produced in its interior many non-jet major flare eruptions (X and M class) that made no CME. During 20-27 October, in contrast to the major-flare eruptions in the interior, six of the homologous jets f…
