Why do accelerating charges emit radiation

In detail the spiral path is a path of tangerine slices. Accelerating charges don't have to radiate. Look at an electron at rest on the earth or constantly accelerating for a long time. It will not radiate. The radiation acceleration formula such as Lamor's only hold for particles with changing acceleration - like a sinusoidal movement. For example, in Feynman's "Lectures on Gravitation" he says "we have inherited a prejudice that an accelerating charge should radiate", and then he goes on to argue that the usual formula giving the power radiated by an accelerating charge as proportional to the square of the acceleration "has led us astray" because it applies only to cyclic or bounded motions.

The second problem is quite tough. Jackson comments, in the introductory remarks of his chapter on 'Radiation Damping, Classical Models of Charged Particles', that we know how to solve classical electrodynamics problems in two ideal conditions - a given charge and current densities, how to compute the fields and b given the fields, how to find the motion of charged particles in their presence. When charged particles accelerate, they do produce radiation which in turn affects the motion of all other charged particles.

However, that problem is, Jackson says, still unsolved. Integrating it to get power radiated gives the famous Larmor formula. You may want to refer to Griffiths' chapter on 'Electromagnetic Radiation'. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. How and why do accelerating charges radiate electromagnetic radiation? Ask Question. Asked 8 years, 5 months ago. Active 4 years, 2 months ago. Viewed 83k times. Improve this question. I am almost a physicist now, I did not continue because the amazing world of programming has captured me so I am working right now!

But someday I will go back and continue studying physics, and it also was mentioned to us but I haven't seen any mathematical derivation.

Otherwise you get pulses with a wide-band spectrum. Add a comment. Active Oldest Votes. Improve this answer. Alfred Centauri Alfred Centauri How an why do accelerating charges radiate electromagnetic radiation? Why EM radiation occurs? How EM radiation occurs? HolgerFiedler HolgerFiedler 8, 4 4 gold badges 18 18 silver badges 54 54 bronze badges. What causes it's acceleration to produce photons and slow it down? As long as an electron isn't under the influence of a field or electromagnetic radiation it doesn't emit photons nor slows down.

Why this question occurs to you? Let's say there is electric field pointing in the opposite direction. The photon Will be accelerating. Will he not be emiting light and slowing down? You had said that if an electron is moving at a constant velocity it it emitting a constant magnetic field.

As you say later a there needs to be an acceleration for produce the magnetic field. I believe at a constant velocity the electron created no magnetic feild. Thank you for the post. Comments RSS. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email.

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Follow Following. Sign me up. In a medium, they interact with the atoms or molecules, and due to this interaction have an apparent speed different from c. When an EM wave travels from one medium with index of refraction n 1 into another medium with a different index of refraction n 2 , then its frequency remains the same, but its speed changes, and therefore it wavelength changes.

For air n is nearly equal to 1, for water n is 1. Most radio waves are emitted by charges oscillating in antennas. The direction of the acceleration of the charges is along the antenna. A radio wave propagates from the antenna to the receiver along a straight-line path called the line of sight. The direction of the electric field E of the electromagnetic radiation emitted by the antenna lies in a plane that contains the antenna and the line of sight to the receiver, and is perpendicular to the line of sight.

The wave is polarized , which means that E has a well defined direction. The electric field is strongest and the intensity highest in the directions perpendicular to the antenna and goes to zero in the direction along the antenna. You get very poor reception if you stand under the antenna. To carry information, the electromagnetic wave must be modulated. The information carried by a radio wave is sound. The amplitude of an AM amplitude modulated radio wave represents the pressure variations, which make up the sound.

The frequency of FM frequency modulated radio waves can be shifted slightly from their nominal carrier frequency. The amount of shift is proportional to the variations in the pressure, which make up the sound.