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Observations of magnetic clouds (MCs) are consistent with the presence of flux ropes detected in the solar wind (SW) a few days after their expulsion from the Sun as coronal mass ejections (CMEs). Both the \textit{in situ} observations of…

Space Physics · Physics 2012-06-07 Adriana Maria Gulisano , Pascal Demoulin , Sergio Dasso , Maria Emilia Ruiz , E. Marsh

We study the writhe, twist and magnetic helicity of different magnetic flux ropes, based on models of the solar coronal magnetic field structure. These include an analytical force-free Titov--D\'emoulin equilibrium solution, non force-free…

Solar and Stellar Astrophysics · Physics 2017-05-10 Y. Guo , E. Pariat , G. Valori , S. Anfinogentov , F. Chen , M. Georgoulis , Y. Liu , K. Moraitis , J. K. Thalmann , S. Yang

Mean-field Variational Bayes (MFVB) is an approximate Bayesian posterior inference technique that is increasingly popular due to its fast runtimes on large-scale datasets. However, even when MFVB provides accurate posterior means for…

Methodology · Statistics 2018-10-18 Ryan Giordano , Tamara Broderick , Michael I. Jordan

The interstellar turbulence is magnetized and thus anisotropic. The anisotropy of turbulent magnetic fields and velocities is imprinted in the related observables, rotation measures (RMs), and velocity centroids (VCs). This anisotropy…

Astrophysics of Galaxies · Physics 2021-04-07 Siyao Xu , Yue Hu

Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux-ropes (FR). In this study, we use Bayesian methods to analyze line-of-sight magnetograms of emerging ARs. We employ a FR model consisting…

Solar and Stellar Astrophysics · Physics 2024-05-21 Mariano Poisson , Marcelo López Fuentes , Cristina H. Mandrini , Pascal Démoulin , Francisco Grings

We present a novel statistical analysis aimed at deriving the intrinsic shapes and magnetic field orientations of molecular clouds using dust emission and polarization observations by the Hertz polarimeter. Our observables are the aspect…

Astrophysics of Galaxies · Physics 2015-05-13 K. Tassis , C. D. Dowell , R. H. Hildebrand , L. Kirby , J. E. Vaillancourt

Stars form inside molecular cloud filaments from the competition of gravitational forces with turbulence and magnetic fields. The exact orientation of these filaments with the magnetic fields depends on the strength of these fields, the…

We report on an observationally constrained analytical model, the INterplanetary Flux ROpe Simulator (INFROS), for predicting the magnetic-field vectors of coronal mass ejections (CMEs) in the interplanetary medium. The main architecture of…

Solar and Stellar Astrophysics · Physics 2020-01-29 Ranadeep Sarkar , Nat Gopalswamy , Nandita Srivastava

Magnetic clouds (MCs) are flux-rope magnetic structures forming a subset of solar coronal mass ejections which have significant space weather impacts. The geoeffectiveness of MCs depends on their properties which evolve during their…

Solar and Stellar Astrophysics · Physics 2021-03-11 Sanchita Pal , Soumyaranjan Dash , Dibyendu Nandy

The problem of bias, meaning over- or underestimation, of the component perpendicular to the line-of-sight, Bperp, in vector magnetic field maps is discussed. Previous works on this topic have illustrated that the problem exists; here we…

Solar and Stellar Astrophysics · Physics 2022-09-28 K. D. Leka , Eric L. Wagner , Ana Belén Griñón-Marín , Véronique Bommier , Richard Higgins

We make the hypothesis that molecular cloud fragments are triaxial bodies with a large scale magnetic field oriented along the short axis. While consistent with theoretical expectations, this idea is supported by magnetic field strength…

Astrophysics · Physics 2009-10-31 Shantanu Basu

Small-scale magnetic flux ropes, in the solar wind, have been studied for decades via the approach of both simulation and observation. Statistical analysis utilizing various in-situ spacecraft measurements is the main observational…

Solar and Stellar Astrophysics · Physics 2019-08-21 Yu Chen , Qiang Hu , Jakobus le Roux

We have studied three Interplanetary Coronal Mass Ejections (ICMEs) having clear signatures of magnetic cloud (MC) arrival at 1 AU and their associated solar sources during 2011 to 2013. Comparing the axial magnetic field strength (B0) of…

Solar and Stellar Astrophysics · Physics 2019-01-30 Ranadeep Sarkar , Nandita Srivastava

We have developed a new automated small-scale magnetic flux rope (SSMFR) detection algorithm based on the Grad-Shafranov (GS) reconstruction technique. We have applied this detection algorithm to the Wind spacecraft in-situ measurements…

Solar and Stellar Astrophysics · Physics 2018-11-28 Qiang Hu , Jinlei Zheng , Yu Chen , Jakobus le Roux , Lulu Zhao

Forbush decreases (FDs) are short-term depressions in the galactic cosmic ray flux and one of the common signatures of coronal mass ejections (CMEs) in the heliosphere. They often show a two-step profile, the second one associated with the…

Solar and Stellar Astrophysics · Physics 2024-01-18 M. Dumbovic , L. Kramaric , I. Benko , B. Heber , B. Vrsnak

The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun's photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full disk…

Solar and Stellar Astrophysics · Physics 2017-10-18 J. A. Linker , R. M. Caplan , C. Downs , P Riley , Z Mikic , R. Lionello , C. J. Henney , C. N. Arge , Y. Liu , M. L. Derosa , A. Yeates , M. J. Owens

Solar pores possess irregular and evolving boundaries that are often far from the ideal circular flux tubes assumed in many magnetohydrodynamic (MHD) oscillation models. To tackle this irregularity in a consistent way for wave analysis, we…

Solar and Stellar Astrophysics · Physics 2026-05-15 T. J. Duckenfield , D. B. Jess , S. Jafarzadeh , L. A. C. A. Schiavo , S. S. A. Silva , S. D. T. Grant

The interaction between interplanetary small-scale magnetic flux ropes and the magnetic field in the ambient solar wind is an important topic to understand- ing the evolution of magnetic structures in the heliosphere. Through a survey of…

Solar and Stellar Astrophysics · Physics 2015-05-19 Hui Tian , Shuo Yao , Qiugang Zong , Jiansen He , Yu Qi

The twisted local magnetic field at the front or rear regions of the magnetic clouds (MCs) associated with interplanetary coronal mass ejections (ICMEs) is often nearly opposite to the direction of the ambient interplanetary magnetic field…

Geomagnetic disturbance forecasting is based on the identification of solar wind structures and accurate determination of their magnetic field orientation. For nowcasting activities, this is currently a tedious and manual process. Focusing…

Space Physics · Physics 2022-02-22 Thomas Narock , Ayris Narock , Luiz F. G. Dos Santos , Teresa Nieves-Chinchilla