scholarly journals Three-dimensional reconstruction of CME-driven shock–streamer interaction from radio and EUV observations: a different take on the diagnostics of coronal magnetic fields

2019 ◽  
Vol 624 ◽  
pp. L2 ◽  
Author(s):  
S. Mancuso ◽  
F. Frassati ◽  
A. Bemporad ◽  
D. Barghini
Keyword(s):  
3D Modeling ◽  
Radial Profile ◽  
Three Dimensional ◽  
Leading Edge ◽  
Spatiotemporal Evolution ◽  
Shock Surface ◽  
Coronal Magnetic Fields ◽  
Dimensional Reconstruction ◽  
Mass Ejection ◽  
The Magnetic Field

On 2014 October 30, a band-splitted type II radio burst associated with a coronal mass ejection (CME) observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) occurred over the southeast limb of the Sun. The fast expansion in all directions of the plasma front acted as a piston and drove a spherical fast shock ahead of it, whose outward progression was traced by simultaneous images obtained with the Nançay Radioheliograph (NRH). The geometry of the CME/shock event was recovered through 3D modeling, given the absence of concomitant stereoscopic observations, and assuming that the band-splitted type II burst was emitted at the intersection of the shock surface with two adjacent low-Alfvén speed coronal streamers. From the derived spatiotemporal evolution of the standoff distance between shock and CME leading edge, we were finally able to infer the magnetic field strength B in the inner corona. A simple radial profile of the form B(r) = (12.6 ± 2.5)r−4 nicely fits our results, together with previous estimates, in the range r = 1.1−2.0 R⊙.

scholarly journals Planar magnetic structures in coronal mass ejection-driven sheath regions

2016 ◽  
Vol 34 (2) ◽  
pp. 313-322 ◽  
Author(s):  
Erika Palmerio ◽  
Emilia K. J. Kilpua ◽  
Neel P. Savani
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Coronal Mass Ejection ◽  
Leading Edge ◽  
Formation Mechanisms ◽  
Single Plane ◽  
Magnetic Structures ◽  
Automated Method ◽  
Mass Ejection ◽  
The Magnetic Field

Abstract. Planar magnetic structures (PMSs) are periods in the solar wind during which interplanetary magnetic field vectors are nearly parallel to a single plane. One of the specific regions where PMSs have been reported are coronal mass ejection (CME)-driven sheaths. We use here an automated method to identify PMSs in 95 CME sheath regions observed in situ by the Wind and ACE spacecraft between 1997 and 2015. The occurrence and location of the PMSs are related to various shock, sheath, and CME properties. We find that PMSs are ubiquitous in CME sheaths; 85 % of the studied sheath regions had PMSs with the mean duration of 6 h. In about one-third of the cases the magnetic field vectors followed a single PMS plane that covered a significant part (at least 67 %) of the sheath region. Our analysis gives strong support for two suggested PMS formation mechanisms: the amplification and alignment of solar wind discontinuities near the CME-driven shock and the draping of the magnetic field lines around the CME ejecta. For example, we found that the shock and PMS plane normals generally coincided for the events where the PMSs occurred near the shock (68 % of the PMS plane normals near the shock were separated by less than 20° from the shock normal), while deviations were clearly larger when PMSs occurred close to the ejecta leading edge. In addition, PMSs near the shock were generally associated with lower upstream plasma beta than the cases where PMSs occurred near the leading edge of the CME. We also demonstrate that the planar parts of the sheath contain a higher amount of strong southward magnetic field than the non-planar parts, suggesting that planar sheaths are more likely to drive magnetospheric activity.

Three- dimensional reconstruction of the thorax in the mongoose (Herpestes ichneumon)

2018 ◽  
Author(s):  
Sema Ozkadif ◽  
Ayse Haligur ◽  
Emrullah Eken
Keyword(s):  
3D Reconstruction ◽  
3D Modeling ◽  
Traffic Accidents ◽  
Three Dimensional ◽  
Thoracic Cavity ◽  
Wild Animals ◽  
Modeling Techniques ◽  
Dimensional Reconstruction ◽  
Modeling Software ◽  
Herpestes Ichneumon

Three- dimensional (3D) reconstruction obtained by using multidetector computed tomography (MDCT) images have widely been used in anatomical studies. Thorax is one of the most important body cavities necessary for the protection of lungs and heart in mammals. Two adult mongooses (1 male, 1 female) obtained from traffic accidents were used in this study. The images obtained from MDCT were stacked and 3D reconstruction of thorax was performed by overlaying images using a 3D modeling software (Mimics 13.1). Some measurements of thoracic cavity, lungs and sternum were taken from the reconstructive images of mongoose and indexes were calculated from these measurements. The morphometric parameters were recorded for both sexes. From the study, it could be concluded that the thoracic cavity, lungs and sternum imagings and findings revealed by 3D modeling techniques can be utilized for anatomical training of wild animals. This study is expected to help in the diagnosis and treatment of thorax diseases in wild animals.

Digital Reconstruction of Demolished Architectural Masterpieces, 3D Modeling, and Animation

2019 ◽  
pp. 206-241
Author(s):  
Roberta Spallone
Keyword(s):  
Case Studies ◽  
3D Modeling ◽  
Three Dimensional ◽  
Horse Racing ◽  
Three Dimensional Reconstruction ◽  
Digital Reconstruction ◽  
Methods And Techniques ◽  
Dimensional Reconstruction ◽  
Critical Approaches

This chapter reviews methods and techniques of digital reconstruction of disappeared architectural masterpieces. Through the overview of theoretical positions are explored heuristic values and communicative potentials of three-dimensional reconstruction, and prerogatives of animation in the interaction with three-dimensional data. Different critical approaches related to the architectures remained on paper are then brought to light. The examination of several case studies, also personally conducted, is extended to unbuilt architectures and minor architectures subject to demolition or transformation in order to highlight the different strategies used for the preservation of the memory of such heritage. Finally, the case study of Turin Horse-Racing Society Building by Carlo Mollino is extensively presented through the analysis of contemporary critical bibliography concerning the project, a description of archival sources and illustration of methods and techniques of the digital reconstruction.

Digital Reconstruction of Demolished Architectural Masterpieces, 3D Modeling, and Animation

2015 ◽  
pp. 476-509 ◽  
Author(s):  
Roberta Spallone
Keyword(s):  
Case Studies ◽  
3D Modeling ◽  
Three Dimensional ◽  
Horse Racing ◽  
Three Dimensional Reconstruction ◽  
Digital Reconstruction ◽  
Methods And Techniques ◽  
Dimensional Reconstruction ◽  
Critical Approaches

This chapter reviews methods and techniques of digital reconstruction of disappeared architectural masterpieces. Through the overview of theoretical positions are explored heuristic values and communicative potentials of three-dimensional reconstruction, and prerogatives of animation in the interaction with three-dimensional data. Different critical approaches related to the architectures remained on paper are then brought to light. The examination of several case studies, also personally conducted, is extended to unbuilt architectures and minor architectures subject to demolition or transformation in order to highlight the different strategies used for the preservation of the memory of such heritage. Finally, the case study of Turin Horse-Racing Society Building by Carlo Mollino is extensively presented through the analysis of contemporary critical bibliography concerning the project, a description of archival sources and illustration of methods and techniques of the digital reconstruction.

scholarly journals Magnetism and the Invisible Man: The mysteries of coronal cavities

2013 ◽  
Vol 8 (S300) ◽  
pp. 139-146 ◽  
Author(s):  
Sarah Gibson
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Interplanetary Space ◽  
Three Dimensional ◽  
Field Measurements ◽  
Coronal Magnetic Field ◽  
Magnetic Structures ◽  
Coronal Magnetic Fields ◽  
Multiple Wavelengths ◽  
The Magnetic Field

AbstractMagnetism defines the complex and dynamic solar corona. Twists and tangles in coronal magnetic fields build up energy and ultimately erupt, hurling plasma into interplanetary space. These coronal mass ejections (CMEs) are transient riders on the ever-outflowing solar wind, which itself possesses a three-dimensional morphology shaped by the global coronal magnetic field. Coronal magnetism is thus at the heart of any understanding of the origins of space weather at the Earth. However, we have historically been limited by the difficulty of directly measuring the magnetic fields of the corona, and have turned to observations of coronal plasma to trace out magnetic structure. This approach is complicated by the fact that plasma temperatures and densities vary among coronal magnetic structures, so that looking at any one wavelength of light only shows part of the picture. In fact, in some regimes it is the lack of plasma that is a significant indicator of the magnetic field. Such a case is the coronal cavity: a dark, elliptical region in which strong and twisted magnetism dwells. I will elucidate these enigmatic features by presenting observations of coronal cavities in multiple wavelengths and from a variety of observing vantages, including unprecedented coronal magnetic field measurements now being obtained by the Coronal Multichannel Polarimeter (CoMP). These observations demonstrate the presence of twisted magnetic fields within cavities, and also provide clues to how and why cavities ultimately erupt as CMEs.

Direct Measurements of the Wing Kinematics of a Bat in Straight Flight

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Sudeep Kumar Singh ◽  
Li-Biao Zhang ◽  
Jing-Shan Zhao
Keyword(s):  
Angle Of Attack ◽  
Three Dimensional ◽  
Leading Edge ◽  
Elastic Membrane ◽  
Wing Kinematics ◽  
Novel Approach ◽  
Dimensional Reconstruction ◽  
Optical Motion ◽  
Optical Motion Capture ◽  
Primary Relationship

Abstract Bat is the only mammal in the nature that can fly. Compared with birds and insects, bats are quite special in that their wings are formed by an elastic membrane, which renders that the airfoil deforms greatly during downstroke and upstroke. Due to the compliant skin of a bat, the movements of its wings are three-dimensionally complex during diverse flight behaviors. To understand the maneuverability and flight performance, three-dimensional reconstruction of the flight kinematics is essential. This study focuses on the reconstruction of the wing kinematics of the bat and identifies the primary relationship of parameters of aerodynamics in straight flight. With markers pasted on the wings and body of a bat, the motions of these points are recorded by a computerized optical motion capture system. The kinematic analysis shows that the motion of wings is very intricate. The digits of the wing display the sign of coupled motion. A novel approach was developed to measure the angle of attack and flapping angle of the wing. The angle of attack of leading edge differs with the overall angle of attack of the wing. The kinematics of the bat's wing is helpful to interpret the secret of the bat's flight.

scholarly journals Initiation of Coronal Mass Ejections by Sunspot Rotation

2013 ◽  
Vol 8 (S300) ◽  
pp. 201-208
Author(s):  
G. Valori ◽  
T. Török ◽  
M. Temmer ◽  
A. M. Veronig ◽  
L. van Driel-Gesztelyi ◽  
...  
Keyword(s):  
Potential Field ◽  
Flux Distribution ◽  
Three Dimensional ◽  
Flux Rope ◽  
Second Phase ◽  
Clockwise Rotation ◽  
Mhd Simulations ◽  
Magnetic Tension ◽  
Mass Ejection ◽  
The Magnetic Field

AbstractWe report observations of a filament eruption, two-ribbon flare, and coronal mass ejection (CME) that occurred in Active Region NOAA 10898 on 6 July 2006. The filament was located South of a strong sunspot that dominated the region. In the evolution leading up to the eruption, and for some time after it, a counter-clockwise rotation of the sunspot of about 30 degrees was observed. We suggest that the rotation triggered the eruption by progressively expanding the magnetic field above the filament. To test this scenario, we study the effect of twisting the initially potential field overlying a pre-existing flux rope, using three-dimensional zero–β MHD simulations. We consider a magnetic configuration whose photospheric flux distribution and coronal structure is guided by the observations and a potential field extrapolation. We find that the twisting leads to the expansion of the overlying field. As a consequence of the progressively reduced magnetic tension, the flux rope quasi-statically adapts to the changed environmental field, rising slowly. Once the tension is sufficiently reduced, a distinct second phase of evolution occurs where the flux rope enters an unstable regime characterized by a strong acceleration. Our simulation thus suggests a new mechanism for the triggering of eruptions in the vicinity of rotating sunspots.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

Sign in / Sign up

Export Citation Format

Share Document