# Synchrotron Radiation: Charge Loss of Relativistic Particles in Magnetic Fields

• Alfredo Tifi
In summary, Elisabetta Liuzzo, an Italian expert of black hole M87, explains that the expected axial radiation coming from M87 black hole should be alike the synchrotron radiation and gives the following definition of synchrotron emission (translating from Italian): "an emission that derives from the loss of charge of relativistic particles immersed in a magnetic field".
Alfredo Tifi
Problem Statement: It is possible to describe synchrotron radiation as caused by a loss of electrical charge of relativistic particles that are moving in a magnetic field?
Relevant Equations: E = mc2

An Italian expert of black hole M87 (Elisabetta Liuzzo) explains that the expected axial radiation coming from M87 black hole should be alike the synchrotron radiation and gives the following definition of synchrotron emission (translating from Italian): "an emission that derives from the loss of charge of relativistic particles immersed in a magnetic field".
This description of electrons or protons losing their electrical charge sounded really odd, but also interesting to me, as a teacher of chemistry.

One day a student of mine asked me if it would be possible to remove the electrical charge from an electron. I thanked him for his very profound question (he was 14), and I answered him that physics does not know what really "is" the electrical charge, although they can measure it. The same holds for the "mass". But in both cases, we can't conceive a physical particle with the electrical charge and mass and the "same" particle without mass or detached by its electrical charge in the same sense we can add or remove varnish from a golf ball.
So, mass and electrical charge are non-additive "interactional or behavioural properties" describing and measured by the interactions in the gravitational and electrical field. Maybe they are derived by something more fundamental, but we don't know what.

Now, we know the link between mass and energy. We understand that particles "became" photons, that is they "lose energy" into photons.
But, if a particle, in the interaction with the magnetic field would lose its charge, I can say anything of the conservation principle of energy as applied to an electrical charge, and anything about the charge conservation principle.

I cannot believe the claim from Liuzzo is completely false, even though it is written in a very popularizing article.

Alfredo Tifi said:
an emission that derives from the loss of charge of relativistic particles immersed in a magnetic field

This is not right. Are you sure the translation is correct?

PAllen said:
This is an extract from Liuzzo’s article “L’ombra del buco nero e la foto del secolo”, published on Magazine Micromega, 4/2019. I copied it from the ebook I’ve bought today. It is not available online. She is speaking about the famous photo...

“L’immagine ci dà inoltre un’altra informazione importante. L’emissione dell’anello luminoso non è simmetrica o omogenea, e nell’immagine infatti si vedono colori più chiari di altri. Le emissioni sono maggiori dove i colori tendono al giallo o al bianco e questo è dovuto al fatto che in queste zone ci sono particelle che si muovono ad altissime velocità: quando la velocità di moto è così alta, le particelle subiscono quelli che vengono chiamati effetti relativistici. L’emissione delle particelle che vi muovono verso di noi è quindi amplificata, cioè ci appare maggiore. In particolare, l’emissione che ci si aspetta è un’emissione di sincrotrone, ovvero un’emissione derivante dalla perdita di carica di particelle relativistiche immerse in un campo magnetico. Quelli che vediamo nell’immagine sono dunque fotoni, emessi dalle velocissime particelle del materiale di accrescimento immerso in un campo magnetico.”
Google translator of bold phrase is almost equal to my translation:
“the emission that is expected is a synchrotron emission, or an emission deriving from the loss of charge of relativistic particles immersed in a magnetic field”.

I would expect the statement at this level to replace “loss of charge” with “motion of charge”. Then it would be accurate for a one sentence allusion to full derivation.

Alfredo Tifi said:
synchrotron emission (translating from Italian): "an emission that derives from the loss of charge of relativistic particles immersed in a magnetic field".
That is a wildly inaccurate description of synchrotron radiation. Also, charge is conserved so it cannot simply be lost. At most it could be passed to other particles.

Alfredo Tifi
Dale said:
That is a wildly inaccurate description of synchrotron radiation. Also, charge is conserved so it cannot simply be lost. At most it could be passed to other particles.
Yeah. What's surprising is the author is a lead researcher on the Event Horizon Telescope. So I am still thinking there was a misquote or something similar, not that she actually said this.

Alfredo Tifi and Dale
That seems more likely to me also.

Since electric charge is and must be strictly conserved due to the gauge invariance of electromagnetism, there can be as much synchrotron radiation as you wish from any electrical charge moving in a magnetic field, this charge will not change the slightest bit. If this were the case, electromagnetic theory wouldn't make any sense anymore and we'd be in a big crises ;-)).

A possibility is that, together with many other articles that have been translated from English in that magazine issues, also Liuzzo's one was originally in English and, as often occurs, badly translated (without her checking!)
I want to try to ask to the redaction, on the behalf of the Principle of Conservation of Electrical Charge.
In case they would answer anything I'll make you know.

vanhees71

## 1. What is synchrotron radiation?

Synchrotron radiation is a type of electromagnetic radiation emitted by charged particles as they are accelerated in a curved trajectory, such as in a synchrotron particle accelerator or in the presence of a strong magnetic field. It is a form of non-thermal radiation, meaning it is not caused by the temperature of the emitting object.

## 2. How is synchrotron radiation produced?

Synchrotron radiation is produced when charged particles, such as electrons, are accelerated in a curved trajectory. As they move, they emit electromagnetic radiation in the form of photons. This radiation can range from radio waves to X-rays, depending on the energy of the particles and the strength of the magnetic field.

## 3. What is the charge loss of relativistic particles in magnetic fields?

The charge loss of relativistic particles in magnetic fields refers to the decrease in the energy of charged particles as they emit synchrotron radiation. This is due to the fact that energy is lost in the form of photons, causing the particles to slow down and lose energy.

## 4. How does synchrotron radiation affect particle accelerators?

Synchrotron radiation can have both positive and negative effects on particle accelerators. On one hand, it can be harnessed and used for experiments and research. On the other hand, it can also cause energy loss and decrease the efficiency of the accelerator, requiring additional energy to maintain the desired particle energy.

## 5. What are the applications of synchrotron radiation?

Synchrotron radiation has a wide range of applications in fields such as physics, chemistry, biology, and materials science. It is used to study the structure and properties of materials, to analyze the composition of samples, and to investigate the behavior of particles and atoms. It is also used in medical imaging and therapy, as well as in industrial processes such as semiconductor manufacturing.

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