American Journal of Physics January 2020January 2020 Issue,

Volume 88, No. 1

 

Electric field lines of relativistically moving point charges https://doi.org/10.1119/10.0000189

Generation of electromagnetic fields by moving charges is a fascinating topic where the tight connection between classical electrodynamics and special relativity becomes particularly apparent. One can gain direct insight into the fascinating structure of such fields by visualizing the electric field lines. However, the calculation of electric field lines for arbitrarily moving charges is far from trivial. Here, we derive an equation for the direction that points from the retarded position of a moving charge towards a specific field line position, which allows for a simple construction of these lines. We analytically solve this equation for several special but important cases: for an arbitrary rectilinear motion, for the motion within the wiggler magnetic field of a free electron laser, and for the motion in a synchrotron.

 

PAPERS

Electric field lines of relativistically moving point charges by Daja Ruhlandt, Steffen Mühle and Jörg Enderlein. DOI: 10.1119/10.0000189

Using Kepler's laws and Rutherford scattering to chart the seven gravity assists in the epic sunward journey of the Parker Solar Probe by Dana Longcope. DOI: 10.1119/10.0000145

Determination of permeability using a classic Darcy water column by Fabian B. Wadsworth, Caron E. J. Vossen, Diana Schmid, Mathieu Colombier, Michael J. Heap, Bettina Scheu and Donald B. Dingwell. DOI: 10.1119/10.0000296

Approximate analytic solution of the potential flow around a rectangle by Eunice J. Kim and Ildoo Kim. DOI: 10.1119/10.0000264

The pulsar search collaboratory: Current status and future prospects by Harsha Blumer, Maura A. McLaughlin, John Stewart, Kathryn Williamson, Duncan R. Lorimer, Sue Ann Heatherly, Joseph K. Swiggum, Ryan S. Lynch, Cabot Zabriskie, Natalia Lewandowska, Aubrey Roy and Shirley Au. DOI: 10.1119/10.0000032

Why are complex numbers needed in quantum mechanics? Some answers for the introductory level by Ricardo Karam. DOI: 10.1119/10.0000258

Reflections in a moving mirror by Mohsen Maesumi. DOI: 10.1119/10.0000172

Relationship between heat capacities derived by different but connected approaches by Ying Liu, Yue Liu and Michael G. B. Drew. DOI: 10.1119/10.0000305

COMPUTATIONAL PHYSICS

Conservative numerical methods for nonlinear oscillators by Mark H. Holmes. DOI: /10.1119/10.0000295

APPARATUS AND DEMONSTRATION NOTES/

Applications of high-speed digital pulse acquisition and software-defined electronics (SDE) in advanced nuclear teaching laboratories by F. D. Becchetti, N. Damron and R. O. Torres-Isea. DOI: 10.1119/1.5125128

BOOK REVIEWS

Celestial Calculations: A Gentle Introduction to Computational Astronomy by Timothy F. Slater. DOI: 10.1119/10.0000284

BOOKS RECEIVED

American Journal of Physics 87, 1020 (2019); https://doi.org/10.1119/10.0000293

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