The Structural Connection between Coronal Mass Ejection Flux Ropes near the Sun and at 1 au

2021 ◽  
Vol 922 (1) ◽  
pp. 64
Author(s):  
H. Xie ◽  
N. Gopalswamy ◽  
S. Akiyama
Keyword(s):  
Extreme Ultraviolet ◽  
Neutral Line ◽  
Flux Rope ◽  
Axial Direction ◽  
Magnetic Clouds ◽  
The Sun ◽  
Solar Cycles ◽  
Weather Forecasts ◽  
Source Regions ◽  
Structural Connection

Abstract We have performed the first comprehensive statistical analysis comparing flux rope (FR) structures of coronal mass ejections (CMEs) near the Sun and at 1 au, using Solar and Heliospheric Observatory and Solar Terrestrial Relations Observatory measurements for the two full solar cycles 23 and 24. This study aims to investigate the physical connection of 102 magnetic FRs among solar source regions, CMEs in the extended corona, and magnetic clouds (MCs) near Earth. Our main results are as follows: (1) We confirmed that the hemispheric-helicity rule holds true for ∼87% of our 102 events. For the 13 events that do not follow this rule, the FR axis directions and helicity signs can be inferred from soft X-ray and extreme ultraviolet images and magnetogram data in the source regions (e.g., coronal arcade skews, Fe xii stalks, sigmoids, and magnetic tongues). (2) Around 25% of the 102 events have rotations >40° between the MC and CME-FR axial orientations. (3) For ∼56% of these rotational events, the FR rotations occurred within the COR2 field of view, which can be predicted from the CME tilts obtained from FR fitting models. In addition, we found that for 89% of the 19 stealth CMEs under study, we were able to use coronal neutral line locations and tilts to predict the FR helicity and its axial direction in the MCs. The above results should help improve the prediction of FR structures in situ. We discuss their implications on space weather forecasts.

scholarly journals The link between CME-associated dimmings and interplanetary magnetic clouds

2008 ◽  
Vol 4 (S257) ◽  
pp. 265-270 ◽  
Author(s):  
Cristina H. Mandrini ◽  
María S. Nakwacki ◽  
Gemma Attrill ◽  
Lidia van Driel-Gesztelyi ◽  
Sergio Dasso ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Large Scale ◽  
Extreme Ultraviolet ◽  
Magnetic Cloud ◽  
Flux Rope ◽  
Magnetic Clouds ◽  
Magnetic Structures ◽  
Doppler Imager ◽  
Imaging Telescope

AbstractCoronal dimmings often develop in the vicinity of erupting magnetic configurations. It has been suggested that they mark the location of the footpoints of ejected flux ropes and, thus, their magnetic flux can be used as a proxy for the ejected flux. If so, this quantity can be compared to the flux in the associated interplanetary magnetic cloud (MC) to find clues about the origin of the ejected flux rope. In the context of this interpretation, we present several events for which we have done a comparative solar-interplanetary analysis. We combine SOHO/Extreme Ultraviolet Imaging Telescope (EIT) data and Michelson Doppler Imager (MDI) magnetic maps to identify and measure the flux in the dimmed regions. We model the associated MCs and compute their magnetic flux using in situ observations. We find that the magnetic fluxes in the dimmings and MCs are compatible in some events; though this is not the case for large-scale and intense eruptions that occur in regions that are not isolated from others. We conclude that, in these particular cases, a fraction of the dimmed regions can be formed by reconnection between the erupting field and the surrounding magnetic structures, via a stepping process that can also explain other CME associated events.

scholarly journals Configuration of a Magnetic Cloud From Solar Orbiter and Wind Spacecraft In-situ Measurements

2021 ◽  
Vol 9 ◽  
Author(s):  
Qiang Hu ◽  
Wen He ◽  
Lingling Zhao ◽  
Edward Lu
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Flux Rope ◽  
3D Models ◽  
Field Configuration ◽  
Magnetic Clouds ◽  
Physical Parameters ◽  
The Sun ◽  
Wind Spacecraft

Coronal mass ejections (CMEs) represent one type of the major eruption from the Sun. Their interplanetary counterparts, the interplanetary CMEs (ICMEs), are the direct manifestations of these structures when they propagate into the heliosphere and encounter one or more observing spacecraft. The ICMEs generally exhibit a set of distinctive signatures from the in-situ spacecraft measurements. A particular subset of ICMEs, the so-called Magnetic Clouds (MCs), is more uniquely defined and has been studied for decades, based on in-situ magnetic field and plasma measurements. By utilizing the latest multiple spacecraft measurements and analysis tools, we report a detailed study of the internal magnetic field configuration of an MC event observed by both the Solar Orbiter (SO) and Wind spacecraft in the solar wind near the Sun-Earth line. Both two-dimensional (2D) and three-dimensional (3D) models are applied to reveal the flux rope configurations of the MC. Various geometrical as well as physical parameters are derived and found to be similar within error estimates for the two methods. These results quantitatively characterize the coherent MC flux rope structure crossed by the two spacecraft along different paths. The implication for the radial evolution of this MC event is also discussed.

scholarly journals LUCI onboard Lagrange, the next generation of EUV space weather monitoring

2020 ◽  
Vol 10 ◽  
pp. 49
Author(s):  
Matthew J. West ◽  
Christian Kintziger ◽  
Margit Haberreiter ◽  
Manfred Gyo ◽  
David Berghmans ◽  
...  
Keyword(s):  
Space Weather ◽  
Extreme Ultraviolet ◽  
Coronal Holes ◽  
Active Regions ◽  
Pass Band ◽  
The Sun ◽  
Lower Corona ◽  
Transient Phenomena ◽  
Weather Forecasts ◽  
Active Pixel

Lagrange eUv Coronal Imager (LUCI) is a solar imager in the Extreme UltraViolet (EUV) that is being developed as part of the Lagrange mission, a mission designed to be positioned at the L5 Lagrangian point to monitor space weather from its source on the Sun, through the heliosphere, to the Earth. LUCI will use an off-axis two mirror design equipped with an EUV enhanced active pixel sensor. This type of detector has advantages that promise to be very beneficial for monitoring the source of space weather in the EUV. LUCI will also have a novel off-axis wide field-of-view, designed to observe the solar disk, the lower corona, and the extended solar atmosphere close to the Sun–Earth line. LUCI will provide solar coronal images at a 2–3 min cadence in a pass-band centred on 19.5. Observations made through this pass-band allow for the detection and monitoring of semi-static coronal structures such as coronal holes, prominences, and active regions; as well as transient phenomena such as solar flares, limb coronal mass ejections (CMEs), EUV waves, and coronal dimmings. The LUCI data will complement EUV solar observations provided by instruments located along the Sun–Earth line such as PROBA2-SWAP, SUVI-GOES and SDO-AIA, as well as provide unique observations to improve space weather forecasts. Together with a suite of other remote-sensing and in-situ instruments onboard Lagrange, LUCI will provide science quality operational observations for space weather monitoring.

scholarly journals Evolutionary signatures in complex ejecta and their driven shocks

2004 ◽  
Vol 22 (10) ◽  
pp. 3679-3698 ◽  
Author(s):  
C. J. Farrugia ◽  
D. B. Berdichevsky
Keyword(s):  
Radial Distance ◽  
Magnetic Clouds ◽  
The Sun ◽  
Solar Cycles ◽  
Time Intervals ◽  
Form Complex ◽  
Event Sequences ◽  
Solar Observations ◽  
Halo Cmes

Abstract. We examine interplanetary signatures of ejecta-ejecta interactions. To this end, two time intervals of inner-heliospheric (≤1AU) observations separated by 2 solar cycles are chosen where ejecta/magnetic clouds are in the process of interacting to form complex ejecta. At the Sun, both intervals are characterized by many coronal mass ejections (CMEs) and flares. In each case, a complement of observations from various instruments on two spacecraft are examined in order to bring out the in-situ signatures of ejecta-ejecta interactions and their relation to solar observations. In the first interval (April 1979), data are shown from Helios-2 and ISEE-3, separated by ~0.33AU in radial distance and 28° in heliographic longitude. In the second interval (March-April 2001), data from the SOHO and Wind probes are combined, relating effects at the Sun and their manifestations at 1AU on one of Wind's distant prograde orbits. At ~0.67AU, Helios-2 observes two individual ejecta which have merged by the time they are observed at 1AU by ISEE-3. In March 2001, two distinct Halo CMEs (H-CMEs) are observed on SOHO on 28-29 March approaching each other with a relative speed of 500kms-1 within 30 solar radii. In order to isolate signatures of ejecta-ejecta interactions, the two event intervals are compared with expectations for pristine (isolated) ejecta near the last solar minimum, extensive observations on which were given by Berdichevsky et al. (2002). The observations from these two event sequences are then intercompared. In both event sequences, coalescence/merging was accompanied by the following signatures: heating of the plasma, acceleration of the leading ejecta and deceleration of the trailing ejecta, compressed field and plasma in the leading ejecta, disappearance of shocks and the strengthening of shocks driven by the accelerated ejecta. A search for reconnection signatures at the interface between the two ejecta in the March 2001 event was inconclusive because the measured changes in the plasma velocity tangential to the interface (Δνt) were not correlated with Δ(Bt /ρ). This was possibly due to lack of sufficient magnetic shear across the interface. The ejecta mergers altered interplanetary parameters considerably, leading to contrasting geoeffects despite broadly similar solar activity. The complex ejecta on 31 March 2001 caused a double-dip ring current enhancement, resulting in two great storms (Dst, corrected for the effect of magnetopause currents, <-450nT), while the merger on 5 April 1979 produced only a corrected Dst of ~-100nT, mainly due to effects of magnetopause currents.

scholarly journals Magnetic clouds seen at different locations in the heliosphere

2008 ◽  
Vol 26 (2) ◽  
pp. 213-229 ◽  
Author(s):  
L. Rodriguez ◽  
A. N. Zhukov ◽  
S. Dasso ◽  
C. H. Mandrini ◽  
H. Cremades ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Interplanetary Space ◽  
Field Configuration ◽  
Magnetic Clouds ◽  
Magnetic Characteristics ◽  
The Sun ◽  
Source Regions ◽  
Plasma Species ◽  
In Situ Observations

Abstract. We analyze two magnetic clouds (MCs) observed in different points of the heliosphere. The main aim of the present study is to provide a link between the different aspects of this phenomenon, starting with information on the origins of the MCs at the Sun and following by the analysis of in-situ observations at 1 AU and at Ulysses. The candidate source regions were identified in SOHO/EIT and SOHO/MDI observations. They were correlated with H-α images that were obtained from ground-based observatories. Hints on the internal magnetic field configuration of the associated coronal mass ejections are obtained from LASCO C2 images. In interplanetary space, magnetic and plasma moments of the distribution function of plasma species (ACE/Ulysses) were analyzed together with information on the plasma composition, and the results were compared between both spacecraft in order to understand how these structures interact and evolve in their cruise from the Sun to 5 AU. Additionally, estimates of global magnitudes of magnetic fluxes and helicity were obtained from magnetic field models applied to the data in interplanetary space. We have found that these magnetic characteristics were well kept from their solar source, up to 5 AU where Ulysses provided valuable information which, together with that obtained from ACE, can help to reinforce the correct matching of solar events and their interplanetary counterparts.

The magnetic flux rope structure of coronal mass ejections – 2021 Julius Bartels Medal Lecture at vEGU

2021 ◽  
Author(s):  
Volker Bothmer
Keyword(s):  
Magnetic Flux ◽  
White Light ◽  
Coronal Mass Ejections ◽  
Large Scale ◽  
Neutral Line ◽  
Source Region ◽  
Flux Rope ◽  
Magnetic Clouds ◽  
Small Scale ◽  
Magnetic Flux Rope

&lt;div&gt; &lt;p&gt;&lt;span&gt;Magnetic clouds are transient solar wind flows in the interplanetary medium with smooth rotations of the magnetic field vector and low plasma beta values. The analysis of magnetic clouds identified in the data of the two Helios spacecraft between 0.3 and 1 AU showed that they can be interpreted to first order by force-free, large-scale, cylindrical magnetic flux tubes. A close correlation of their occurrences was found with disappearing filaments at the Sun. The magnetic clouds that originated from the northern solar hemisphere showed predominantly left-handed magnetic helicities and the ones from the southern hemisphere predominantly right-handed ones. They were often preceded by an interplanetary shock wave and some were found to be directly following a coronal mass ejection towards the Helios spacecraft as detected by the Solwind coronagraph on board the P78-1 satellite. With the SOHO mission unprecedented long-term observations of coronal mass ejections (CMEs) were taken with the LASCO coronagraphs, with a spatial and time resolution that allowed to investigate their internal white-light fine structure. With complementary photospheric and EUV observations from SOHO, CMEs were found to arise from pre-existing small scale loop systems, overlying regions of opposite magnetic polarities. From the characteristic pattern of their source regions in both solar hemispheres, a generic scheme was presented in which their projected white-light topology depends primarily on the orientation and position of the source region&amp;#8217;s neutral line on the solar disk. Based on this interpretation the graduated cylindrical shell method was developed, which allowed to model the electron density distribution of CMEs as 3D flux ropes. This concept was validated through stereoscopic observations of CMEs taken by the coronagraphs of the SECCHI remote sensing suite on board the twin STEREO spacecraft. The observations further revealed that the dynamic near-Sun evolution of CMEs often leads to distortions of their flux rope structure. However, the magnetic flux rope concept of CMEs is today one of the fundamental methods in space weather forecasts. With the Parker Solar Probe we currently observe for the first time CMEs in-situ and remotely at their birthplaces in the solar corona and can further unravel their origin and evolution from the corona into the heliosphere. This lecture provides a state-of-the-art overview on the magnetic structure of CMEs and includes latest observations from the Parker Solar Probe mission.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;

scholarly journals Evolution of interplanetary coronal mass ejections and magnetic clouds in the heliosphere

2013 ◽  
Vol 8 (S300) ◽  
pp. 245-254
Author(s):  
Pascal Démoulin
Keyword(s):  
Solar Wind ◽  
Physical Properties ◽  
Coronal Mass Ejections ◽  
Magnetic Measurements ◽  
Flux Rope ◽  
Magnetic Clouds ◽  
The Sun ◽  
Interplanetary Coronal Mass Ejections

AbstractInterplanetary Coronal Mass Ejections (ICMEs), and more specifically Magnetic Clouds (MCs), are detected with in situ plasma and magnetic measurements. They are the continuation of the CMEs observed with imagers closer to the Sun. A review of their properties is presented with a focus on their magnetic configuration and its evolution. Many recent observations, both in situ and with imagers, point to a key role of flux ropes, a conclusion which is also supported by present coronal eruptive models. Then, is a flux rope generically present in an ICME? How to quantify its 3D physical properties when it is detected locally as a MC? Is it a simple flux rope? How does it evolve in the solar wind? This paper reviews our present answers and limited understanding to these questions.

scholarly journals Radial Sizes and Expansion Behavior of ICMEs in Solar Cycles 23 and 24

2021 ◽  
Vol 8 ◽  
Author(s):  
Wageesh Mishra ◽  
Urmi Doshi ◽  
Nandita Srivastava
Keyword(s):  
Magnetic Clouds ◽  
Radial Expansion ◽  
The Sun ◽  
Solar Cycles ◽  
Future Studies ◽  
Expansion Behavior ◽  
Cycle 24 ◽  
Later Phase ◽  
Radial Propagation

We attempt to understand the influence of the heliospheric state on the expansion behavior of coronal mass ejections (CMEs) and their interplanetary counterparts (ICMEs) in solar cycles 23 and 24. Our study focuses on the distributions of the radial sizes and duration of ICMEs, their sheaths, and magnetic clouds (MCs). We find that the average radial size of ICMEs (MCs) at 1 AU in cycle 24 is decreased by ∼33% (∼24%) of its value in cycle 23. This is unexpected as the reduced total pressure in cycle 24 should have allowed the ICMEs in cycle 24 to expand considerably to larger sizes at 1 AU. To understand this, we study the evolution of radial expansion speeds of CME-MC pairs between the Sun and Earth based on their remote and in situ observations. We find that radial expansion speeds of MCs at 1 AU in solar cycles 23 and 24 are only 9 and 6%, respectively, of their radial propagation speeds. Also, the fraction of radial propagation speeds as expansion speeds of CMEs close to the Sun are not considerably different between solar cycles 23 and 24. We also find a constant (0.63 ± 0.1) dimensionless expansion parameter of MCs at 1 AU for both solar cycles 23 and 24. We suggest that the reduced heliospheric pressure in cycle 24 is compensated by the reduced magnetic content inside CMEs/MCs, which did not allow the CMEs/MCs to expand enough in the later phase of their propagation. Furthermore, the average radial sizes of sheaths are the same in both cycles, which is unexpected, given the weaker CMEs/ICMEs in cycle 24. We discuss the possible causes and consequences of our findings relevant for future studies.

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