# Relativistic particles losing their charge 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.

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#### PAllen

Staff Emeritus
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?

#### Alfredo Tifi

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”.

#### PAllen

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.

#### Dale

Mentor
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.

#### PAllen

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.

#### Dale

Mentor
That seems more likely to me also.

#### vanhees71

Gold Member
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 ;-)).

#### Alfredo Tifi

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 wanna 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.

"Relativistic particles losing their charge in a magnetic field?"

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