scholarly journals On the pulsar velocity–magnetic field correlation

1995 ◽  
Vol 275 (1) ◽  
pp. L16-L18 ◽  
Author(s):  
D. R. Lorimer ◽  
A. G. Lyne ◽  
B. Anderson
Keyword(s):  
Magnetic Field ◽  
Pulsar Velocity ◽  
Field Correlation

Theory and observations of switchbacks’ evolution in the solar wind

2021 ◽  
Author(s):  
Anna Tenerani ◽  
Marco Velli ◽  
Lorenzo Matteini
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Radial Magnetic Field ◽  
Open Questions ◽  
Coronal Activity ◽  
Turbulent Heating ◽  
Field Lines ◽  
Radial Evolution ◽  
Field Correlation

<p>Alfvénic fluctuations represent the dominant contributions to turbulent fluctuations in the solar wind, especially, but not limited to, the fastest streams with velocity of the order of 600-700 km/s. Alfvénic fluctuations can contribute to solar wind heating and acceleration via wave pressure and turbulent heating. Observations show that such fluctuations are characterized by a nearly constant magnetic field amplitude, a condition which remains largely to be understood and that may be an indication of how fluctuations evolve and relax in the expanding solar wind. Interestingly, measurements from Parker Solar Probe have shown the ubiquitous and persistent presence of the so-called switchbacks. These are magnetic field lines which are strongly perturbed to the point that they produce local inversions of the radial magnetic field. The corresponding signature of switchbacks in the velocity field is that of local enhancements in the radial speed (or jets) that display the typical velocity-magnetic field correlation that characterizes Alfvén waves propagating away from the Sun. While there is not yet a general consensus on what is the origin of switchbacks and their connection to coronal activity, a first necessary step to answer these important questions is to understand how they evolve and how long they can persist in the solar wind. Here we investigate the evolution of switchbacks. We address how their evolution is affected by parametric instabilities and the possible role of expansion, by comparing models with the observed radial evolution of the fluctuations’ amplitude. We finally discuss what are the implications of our results for models of switchback generation and related open questions.</p>

Elevated Brain Iron in Cocaine Use Disorder as Indexed by Magnetic Field Correlation Imaging

2019 ◽  
Vol 4 (6) ◽  
pp. 579-588
Author(s):  
Vitria Adisetiyo ◽  
Corinne E. McGill ◽  
William H. DeVries ◽  
Jens H. Jensen ◽  
Colleen A. Hanlon ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Brain Iron ◽  
Cocaine Use ◽  
Field Correlation

scholarly journals Velocity-Magnetic Field Correlation of Pulsars

1996 ◽  
Vol 160 ◽  
pp. 49-50
Author(s):  
Naoki Itoh ◽  
Takemi Kotouda
Keyword(s):  
Magnetic Field ◽  
Constant Magnetic Field ◽  
Field Model ◽  
Transverse Velocity ◽  
Distribution Model ◽  
Recent Measurement ◽  
Apparent Correlation ◽  
Magnetic Field Model ◽  
Field Correlation ◽  
The Magnetic Field

Monte Carlo simulations of the evolution of pulsars are carried out in order to compare with the recent measurement of the pulsar transverse velocity by Lyne & Lorimer (1994). The new electron density distribution model of Taylor & Cordes (1993) is adopted in the simulation. Accurate pulsar orbits in the Galactic gravitational field are calculated. It is found that the constant magnetic field model of pulsars can account for the new measurement of the pulsar transverse velocity and the apparent correlation between the strength of the magnetic field and the transverse velocity of the pulsars. The present finding confirms the validity of the constant magnetic field model of pulsars and consolidates the idea that the apparent correlation between the strength of the magnetic field and the transverse velocity of the pulsars is caused by observational selection effects.

Reconstruction of the magnetic connection from Mercury to the solar corona

2020 ◽  
Author(s):  
Alessandro Ippolito ◽  
Christina Plainaki ◽  
Gaetano Zimbardo ◽  
Stefano Massetti ◽  
Anna Milillo
Keyword(s):  
Magnetic Field ◽  
Solar Corona ◽  
Magnetic Data ◽  
Monte Carlo Code ◽  
Correlation Lengths ◽  
Magnetic Fluctuation ◽  
Magnetic Field Model ◽  
Field Lines ◽  
Field Correlation ◽  
Accelerated Particles

<p>The magnetic foot point of Mercury on the solar disk has been reconstructed for selected case studies, in order to better understand the interaction between the solar corona and the planet. The transport of the magnetic field lines in the heliosphere is here evaluated with a Monte Carlo code that gives a random displacement at each step of the integration along the Parker magnetic field model. Such displacement is proportional to a “local” diffusion coefficient, which is a function of the fluctuation level and magnetic field correlation lengths. The simulation is tailored to specific events by using the observed values of solar wind velocity and magnetic fluctuation levels. Magnetic data from MAG/MESSENGER have been considered to compute the magnetic fluctuation level, while, concerning proton fluxes, FIPS/MESSENGER data has been taken into account. A number of SEP events observed on Mercury during 2011 and 2012 have been analysed, studying, for each event, the magnetic connection from Mercury to the solar corona, and the position of the active region possibly source of the accelerated particles observed.</p>

scholarly journals PULSAR VELOCITIES DUE TO VIOLATION OF THE EQUIVALENCE PRINCIPLE BY NEUTRINOS

1998 ◽  
Vol 13 (29) ◽  
pp. 2379-2384 ◽  
Author(s):  
R. HORVAT
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Neutrino Oscillation ◽  
Equivalence Principle ◽  
Oscillation Mechanism ◽  
Pulsar Velocity

We consider the pulsar velocity problem and relate it to some unconventional neutrino oscillation mechanisms based on the violation of the equivalence principle by neutrinos. We show that the observed pulsar velocities may be explained by violations at the level from 10-9 to 10-10 in the case of a non-universal tensor neutrino-gravity coupling, whereas there is no solution in the case of a non-universal scalar neutrino-gravity coupling. Neutrinos may remain massless and the requisite magnetic field strength is similar to that in the conventional mass oscillation mechanism.

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