Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Classical Physics
Quantum Physics
Quantum Interpretations
Special and General Relativity
Atomic and Condensed Matter
Nuclear and Particle Physics
Beyond the Standard Model
Cosmology
Astronomy and Astrophysics
Other Physics Topics
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Classical Physics
Quantum Physics
Quantum Interpretations
Special and General Relativity
Atomic and Condensed Matter
Nuclear and Particle Physics
Beyond the Standard Model
Cosmology
Astronomy and Astrophysics
Other Physics Topics
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Physics
Special and General Relativity
Relativistic conduction current density?
Reply to thread
Message
[QUOTE="ChristopherMDS, post: 5510785, member: 598351"] Hello, I am an electrical engineer rather than a physicist, however, I am trying to understand the physics of a twin wire transmission line in terms of the charge and current density. Let's say we have a lossless, infinite length, twin wire transmission line, a step current is induced into the line and the signal wavefront propagates at the speed of light from the start to the line to infinite. My physical understanding is that conventional current moves on average at drift velocity (a few mm/second) even though the signal propagates at the speed of light. This is due to the fact that the lines are electrically neutral and the electric field associated with the wavefront traveling at the speed of light is terminated by mobile charges moving slightly toward or away from the conductor surface, bearing in mind that the lattice is fixed positive charge. This effectively supplies the surface charges terminating the transverse electric field. Now, my thoughts were confirmed by the book 'The Power and Beauty of Electromagnetic Fields', by [URL='http://eu.wiley.com/WileyCDA/Section/id-302479.html?query=Frederic+R.+Morgenthaler']Frederic R. Morgenthaler[/URL]. (Chapter 18 - TEM Transmission Lines - pg. 189-191) However, as my knowledge of relativity is rather limited, I am struggling to understand one of his equations; j(x,y)=ρ[SUB]0[/SUB](x,y)c which he calls the relativistic current-density as c is the speed of light. He says this equation "arises from imposition of the Lorentz-gauge and conservation of charge", without any derivation. I do not know where this comes from and physically its distinction from my classical understanding of convection current density j=ρu where u is the drift velocity. It appears that his equation is a fictional current density relating to the relativistic signal propagating at the speed of light? Can anyone shed any light on this equation or provide a derivation? Thanks in advance, apologies for any ignorance on my behalf... Regards, Chris [/QUOTE]
Insert quotes…
Post reply
Forums
Physics
Special and General Relativity
Relativistic conduction current density?
Back
Top