The sheath region of April 2020 magnetic cloud and the associated energetic ions 

2021 ◽  
Author(s):  
Emilia Kilpua ◽  
Simon Good ◽  
Nina Dresing ◽  
Rami Vainio ◽  
Emma Davies ◽  
...  
Keyword(s):  
Flux Rope ◽  
Leading Edge ◽  
Heliospheric Current Sheet ◽  
Acceleration Process ◽  
Astrophysical Plasmas ◽  
Energetic Ions ◽  
Sheath Region ◽  
Open Questions ◽  
Mass Ejection

<p>Acceleration of energetic particles is a fundamental and ubiquitous mechanism in space and astrophysical plasmas. One of the open questions is the role of the sheath region behind the shock in the acceleration process. We analyze observations by Solar Orbiter, BepiColombo and the L1 spacecraft to explore the structure of a coronal mass ejection (CME)-driven sheath and its relation to enhancements of energetic ions that occurred on April 19-20, 2020. Our detailed analysis of the magnetic field, plasma and particle observations show that the enhancements were related to the Heliospheric Current Sheet crossings related to the reconnecting current sheets in the vicinity of the shock and a mini flux rope that was compressed at the leading edge of the CME ejecta. This study highlights the importance of smaller-scale sheath structures for the energization process. These structures likely formed already closer to the Sun and were swept and compressed from the upstream wind past the shock into the sheath. The upcoming observations by the recent missions (Solar Orbiter, Parker Solar Probe and BepiColombo) provide an excellent opportunity to explore further their role.  </p>

Observations for the Role of Flux rope Eruption in a Geoeffective Solar Flare

2014 ◽  
Vol 4 (2) ◽  
pp. 555-564
Author(s):  
A.M Aslam
Keyword(s):  
Solar Flare ◽  
Flux Rope ◽  
Magnetic Configuration ◽  
Solar Dynamics Observatory ◽  
Multi Wavelength ◽  
Solar Dynamics ◽  
Halo Coronal Mass Ejection ◽  
Mass Ejection ◽  
The Waves

On September 24, 2011 a solar flare of M 7.1 class was released from the Sun. The flare was observed by most of the space and ground based observatories in various wavebands. We have carried out a study of this flare to understand its causes on Sun and impact on earth. The flare was released from NOAA active region AR 11302 at 12:33 UT. Although the region had already produced many M class flares and one X- class flare before this flare, the magnetic configuration was not relaxed and still continued to evolve as seen from HMI observations. From the Solar Dynamics Observatory (SDO) multi-wavelength (131 Ã…, 171 Ã…, 304 Ã… and 1600Ã…) observations we identified that a rapidly rising flux rope triggered the flare although HMI observations revealed that magnetic configuration did not undergo a much pronounced change. The flare was associated with a halo Coronal Mass Ejection (CME) as recorded by LASCO/SOHO Observations. The flare associated CME was effective in causing an intense geomagnetic storm with minimum Dst index -103 nT. A radio burst of type II was also recorded by the WAVES/WIND. In the present study attempt is made to study the nature of coupling between solar transients and geospace.

scholarly journals The role of streamers in the deflection of coronal mass ejections

2011 ◽  
Vol 7 (S286) ◽  
pp. 134-138
Author(s):  
F. P. Zuccarello ◽  
A. Bemporad ◽  
C. Jacobs ◽  
M. Mierla ◽  
S. Poedts ◽  
...  
Keyword(s):  
Current Sheet ◽  
Three Dimensional ◽  
Heliospheric Current Sheet ◽  
Field Of View ◽  
Physical Explanation ◽  
Filament Eruption ◽  
Mhd Simulations ◽  
Radial Evolution ◽  
Mass Ejection

AbstractOn 2009 September 21, a filament eruption and the associated Coronal Mass Ejection (CME) was observed by the STEREO spacecraft. The CME originated from the southern hemisphere and showed a deflection of about 15° towards the heliospheric current sheet (HCS) during its propagation in the COR1 field-of-view (FOV). The aim of this paper is to provide a physical explanation for the strong deflection of the CME. We first use the STEREO observations in order to reconstruct the three dimensional (3D) trajectory of the CME. Starting from a magnetic configuration that closely resembles the potential field extrapolation for that date, we performed numerical magneto-hydrodynamics (MHD) simulations. By applying localized shearing motions, a CME is initiated in the simulation, showing a similar non-radial evolution, structure, and velocity as the observed event. The CME gets deflected towards the current sheet of the larger northern helmet streamer, due to an imbalance in the magnetic pressure and tension forces and finally it gets into the streamer and propagates along the heliospheric current sheet.

scholarly journals The role of non-axisymmetry of magnetic flux rope in constraining solar eruptions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ze Zhong ◽  
Yang Guo ◽  
M. D. Ding
Keyword(s):  
Magnetic Field ◽  
Lorentz Force ◽  
Flux Rope ◽  
Radial Magnetic Field ◽  
Magnetic Flux Rope ◽  
Background Magnetic Field ◽  
Solar Eruptions ◽  
Magnetohydrodynamic Simulation ◽  
Mass Ejection

AbstractWhether a solar eruption is successful or failed depends on the competition between different components of the Lorentz force exerting on the flux rope that drives the eruption. The present models only consider the strapping force generated by the background magnetic field perpendicular to the flux rope and the tension force generated by the field along the flux rope. Using the observed magnetic field on the photosphere as a time-matching bottom boundary, we perform a data-driven magnetohydrodynamic simulation for the 30 January 2015 confined eruption and successfully reproduce the observed solar flare without a coronal mass ejection. Here we show a Lorentz force component, resulting from the radial magnetic field or the non-axisymmetry of the flux rope, which can essentially constrain the eruption. Our finding contributes to the solar eruption model and presents the necessity of considering the topological structure of a flux rope when studying its eruption behaviour.

On the Role of Magnetic Fields in an Erupting Solar Filament

2019 ◽  
Vol 15 (S354) ◽  
pp. 452-453
Author(s):  
Qiao Song ◽  
Shuhong Yang ◽  
Jing-Song Wang
Keyword(s):  
Magnetic Fields ◽  
Space Weather ◽  
Extreme Ultraviolet ◽  
Flux Rope ◽  
Solar Dynamics Observatory ◽  
Driving Mechanisms ◽  
Solar Filament ◽  
Solar Dynamics ◽  
Mass Ejection

AbstractA filament eruption may lead to a coronal mass ejection (CME), which is one of the main driving mechanisms of space weather. This work analyses a slow and flareless CME event associated with an erupting quiescent filament. By using the extreme ultraviolet images of the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, we trace the evolution of the filament in detail, and present the manifestations of the role of magnetic fields in the low corona. The results suggest the existence of a magnetic flux rope in the pre-eruption structures. Our study of this complex magnetic system may lead to a better understanding of CMEs and their impact on the space weather.

scholarly journals Unusual enhancement of ~ 30 MeV proton flux in an ICME sheath region

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Mitsuo Oka ◽  
Takahiro Obara ◽  
Nariaki V. Nitta ◽  
Seiji Yashiro ◽  
Daikou Shiota ◽  
...  
Keyword(s):  
Shock Front ◽  
Energetic Particle ◽  
Leading Edge ◽  
Solar Energetic Particle ◽  
Interplanetary Shock ◽  
Proton Event ◽  
Sheath Region ◽  
Time Profiles ◽  
Energetic Particle Flux ◽  
Mev Protons

AbstractIn gradual Solar Energetic Particle (SEP) events, shock waves driven by coronal mass ejections (CMEs) play a major role in accelerating particles, and the energetic particle flux enhances substantially when the shock front passes by the observer. Such enhancements are historically referred to as Energetic Storm Particle (ESP) events, but it remains unclear why ESP time profiles vary significantly from event to event. In some cases, energetic protons are not even clearly associated with shocks. Here, we report an unusual, short-duration proton event detected on 5 June 2011 in the compressed sheath region bounded by an interplanetary shock and the leading edge of the interplanetary CME (or ICME) that was driving the shock. While < 10 MeV protons were detected already at the shock front, the higher-energy (> 30 MeV) protons were detected about four hours after the shock arrival, apparently correlated with a turbulent magnetic cavity embedded in the ICME sheath region.

scholarly journals Farm Animals Are Long Away from Natural Behavior: Open Questions and Operative Consequences on Animal Welfare

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 724
Author(s):  
Alberto Cesarani ◽  
Giuseppe Pulina
Keyword(s):  
Animal Welfare ◽  
Farm Animal ◽  
Farm Animals ◽  
Natural State ◽  
Natural Behavior ◽  
Welfare Assessment ◽  
Open Questions ◽  
Naive Approach

The concept of welfare applied to farm animals has undergone a remarkable evolution. The growing awareness of citizens pushes farmers to guarantee the highest possible level of welfare to their animals. New perspectives could be opened for animal welfare reasoning around the concept of domestic, especially farm, animals as partial human artifacts. Therefore, it is important to understand how much a particular behavior of a farm animal is far from the natural one of its ancestors. This paper is a contribution to better understand the role of genetics of the farm animals on their behavior. This means that the naïve approach to animal welfare regarding returning animals to their natural state should be challenged and that welfare assessment should be considered.

scholarly journals miR-205 in Breast Cancer: State of the Art

2020 ◽  
Vol 22 (1) ◽  
pp. 27
Author(s):  
Ilaria Plantamura ◽  
Alessandra Cataldo ◽  
Giulia Cosentino ◽  
Marilena V. Iorio
Keyword(s):  
Breast Cancer ◽  
Cancer Progression ◽  
Normal Breast ◽  
Response To Therapy ◽  
Aberrant Expression ◽  
Open Questions ◽  
Tumor Tissues ◽  
Breast Physiology ◽  
Cancer Types

Despite its controversial roles in different cancer types, miR-205 has been mainly described as an oncosuppressive microRNA (miRNA), with some contrasting results, in breast cancer. The role of miR-205 in the occurrence or progression of breast cancer has been extensively studied since the first evidence of its aberrant expression in tumor tissues versus normal counterparts. To date, it is known that the expression of miR-205 in the different subtypes of breast cancer is decreasing from the less aggressive subtype, estrogen receptor/progesterone receptor positive breast cancer, to the more aggressive, triple negative breast cancer, influencing metastasis capability, response to therapy and patient survival. In this review, we summarize the most important discoveries that have highlighted the functional role of this miRNA in breast cancer initiation and progression, in stemness maintenance, in the tumor microenvironment, its potential role as a biomarker and its relevance in normal breast physiology—the still open questions. Finally, emerging evidence reveals the role of some lncRNAs in breast cancer progression as sponges of miR-205. Here, we also reviewed the studies in this field.

scholarly journals Electroreduction of Bi(III) ions in the aspect of expanding the “cap-pair” effect: the role of the nanosized active complexes

2021 ◽  
Author(s):  
Agnieszka Nosal-Wiercińska ◽  
Marlena Martyna ◽  
Sławomira Skrzypek ◽  
Anna Szabelska ◽  
Małgorzata Wiśniewska
Keyword(s):  
Electrolyte Concentration ◽  
Supporting Electrolyte ◽  
Acceleration Process ◽  
Organic Substances ◽  
Effect Mechanism ◽  
Solution Interface

AbstractThe paper discusses the electroreduction of Bi(III) ions in the aspect of expanding the “cap-pair” effect.The “cap-pair” rule is associated with the acceleration of the electrode’s processes by organic substances. The interpretation of the “cap-pair” effect mechanism was expanded to include the effect of supporting electrolyte concentration on the acceleration process and the type of electrochemical active as well as used protonated organic substances. It has also been shown that the phenomena occurring at the electrode/solution interface can influence a change in the dynamics of the electrode’s process according to the “cap-pair” rule.

scholarly journals How Can Psychological Science Help Counter the Spread of Fake News?

2021 ◽  
Vol 24 ◽  
Author(s):  
Sander van der Linden ◽  
Jon Roozenbeek ◽  
Rakoen Maertens ◽  
Melisa Basol ◽  
Ondřej Kácha ◽  
...  
Keyword(s):  
Research Agenda ◽  
Source Credibility ◽  
Fake News ◽  
Intervention Effectiveness ◽  
Motivated Cognition ◽  
Individual Level ◽  
Psychological Science ◽  
Open Questions ◽  
The Individual

Abstract In recent years, interest in the psychology of fake news has rapidly increased. We outline the various interventions within psychological science aimed at countering the spread of fake news and misinformation online, focusing primarily on corrective (debunking) and pre-emptive (prebunking) approaches. We also offer a research agenda of open questions within the field of psychological science that relate to how and why fake news spreads and how best to counter it: the longevity of intervention effectiveness; the role of sources and source credibility; whether the sharing of fake news is best explained by the motivated cognition or the inattention accounts; and the complexities of developing psychometrically validated instruments to measure how interventions affect susceptibility to fake news at the individual level.

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