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Related papers: Velocity Gradients as a Tracer for Magnetic Fields

200 papers

Vertical excursion fixed-field alternating gradient accelerators can be designed with tunes that are invariant with respect to momentum and trajectories that are scaled images of each other displaced only in the vertical direction. This is…

Accelerator Physics · Physics 2021-03-03 S. Machida , D. J. Kelliher , J-B. Lagrange , C. T. Rogers

Cool giant and supergiant stars generally present low velocity winds with high mass loss rates. Several models have been proposed to explain the acceleration process of these winds. Although dust is known to be present in these objects, the…

Astrophysics · Physics 2009-11-11 A. A. Vidotto , D. Falceta-Goncalves , V. Jatenco-Pereira

Abrupt large events in the Alfv\'{e}nic and sub-Alfv\'{e}nic frequency bands in tokamaks are typically correlated with increased fast ion loss. Here, machine learning is used to speed up the laborious process of characterizing the behaviour…

With the ultimate aim of using the fundamental or $f$-mode to study helioseismic aspects of turbulence-generated magnetic flux concentrations, we use randomly forced hydromagnetic simulations of a piecewise isothermal layer in two…

Solar and Stellar Astrophysics · Physics 2015-06-19 Nishant K. Singh , Axel Brandenburg , S. M. Chitre , Matthias Rheinhardt

One of the tools that can provide evidence about the existence of helical magnetic fields in AGN is the observation of rotation measure gradients across the jet. Such observations have been previously made successfully, proving that such…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 J. C. Algaba

We estimate the polarized thermal dust emission from MHD simulations of protostellar collapse and outflow formation in order to investigate alignment of outflows with magnetic fields. The polarization maps indicate that alignment of an…

Astrophysics · Physics 2009-11-13 Tomoaki Matsumoto , Takeshi Nakazato , Kohji Tomisaka

When magnetohydrodynamic turbulence evolves in the presence of a large-scale mean magnetic field, an anisotropy develops relative to that preferred direction. The well-known tendency is to develop stronger gradients perpendicular to the…

Plasma Physics · Physics 2020-07-15 Rohit Chhiber , William H. Matthaeus , Sean Oughton , Tulasi N. Parashar

We report on precise measurements of magnetic field gradients extracted from transverse relaxation rates of precessing spin samples. The experimental approach is based on the free precession of gaseous, nuclear spin polarized $^3$He and…

Using $10,\!080^3$ grid simulations, we analyze scale-dependent alignment in driven, compressible, no net-flux magnetohydrodynamic turbulence. The plasma self-organizes into localized, strongly aligned regions. Alignment spans all primitive…

Plasma Physics · Physics 2025-04-23 James R. Beattie , Amitava Bhattacharjee

We present a study of the magnetic field of the Small Magellanic Cloud (SMC), carried out using radio Faraday rotation and optical starlight polarization data. Consistent negative rotation measures (RMs) across the SMC indicate that the…

Recent observations revealed that small magnetic elements abundant at the solar surface move poleward with a velocity which seems to be lower than the plasma velocity $U_{\theta}$. Guerrero et al. (2011) explained this discrepancy as a…

Solar and Stellar Astrophysics · Physics 2015-06-03 G. Guerrero , M. Rheinhardt , M. Dikpati

The role of magnetic fields in the dynamical evolution of galaxies and of the interstellar medium (ISM) is not well understood, mainly because such fields are difficult to directly observe. Radio astronomy provides the best tools to measure…

Astrophysics · Physics 2009-11-10 R. Beck , B. M. Gaensler

Cosmic rays accelerated by a shock form a streaming distribution of outgoing particles in the foreshock region. If the ambient fields are negligible compared to the shock and cosmic ray energetics, a stronger magnetic field can be generated…

Astrophysics · Physics 2011-02-11 Mikhail V. Medvedev , Olga V. Zakutnyaya

We present a new microscopic ODE-based model for pedestrian dynamics: the Gradient Navigation Model. The model uses a superposition of gradients of distance functions to directly change the direction of the velocity vector. The velocity is…

Mathematical Physics · Physics 2014-06-11 Felix Dietrich , Gerta Köster

This paper presents a novel approach for vehicle localization by leveraging the ambient magnetic field within a given environment. Our approach involves introducing a global mathematical function for magnetic field mapping, combined with…

Robotics · Computer Science 2024-11-12 Mrunmayee Deshpande , Manoranjan Majji , J. Humberto Ramos

We propose and demonstrate an experimental implementation for the observation of magnetic fields from spatial features of absorption profiles in a warm atomic vapor. A radially polarized vector beam that traverses an atomic vapor will…

We consider the "kinematics" of spacelike congruences and apply them to a family of self-gravitating magnetic forcelines. Our aim is to investigate the convergence and the possible focusing of these lines, as well as their rotation and…

General Relativity and Quantum Cosmology · Physics 2017-09-28 Vangelis Giantsos , Christos G. Tsagas

We study possibility of obtaining velocity spectra by studying turbulence in an optically thick medium using velocity centroids (VCs).We find that the regime of universal, i.e. independent of underlying turbulence statistics, fluctuations…

Astrophysics of Galaxies · Physics 2016-10-12 D. Kandel , A. Lazarian , D. Pogosyan

We investigate the transition of the solar wind turbulent cascade from MHD to sub-ion range by means of a detail comparison between in situ observations and hybrid numerical simulations. In particular we focus on the properties of the…

Space Physics · Physics 2020-09-01 L. Matteini , L. Franci , O. Alexandrova , C. Lacombe , S. Landi , P. Hellinger , E. Papini , A. Verdini

Alfv\'enic motions are ubiquitous in the solar atmosphere and their observed properties are closely linked to those of photospheric p-modes. However, it is still unclear how a predominantly acoustic wave driver can produce these transverse…

Solar and Stellar Astrophysics · Physics 2023-05-31 Samuel Skirvin , Yuhang Gao , Tom Van Doorsselaere