Talk:Heaviside–Lorentz units

message: Which Heaviside?  Which Lorentz?  The article should say.  121a0012 (talk) 04:40, 16 October 2010 (UTC)
replies: text: Done. Dicklyon (talk) 07:01, 16 October 2010 (UTC)
thread_title:  Identify people 

message: Of names, see: german wikipedia:  Es ist nach Oliver Heaviside und Hendrik Antoon Lorentz benannt. (it is named after OH and HAL)
The system roughly follows the gaussian scale, in that epsilon and mu (electric and magnetic constants), are unity, but change the size of the derived measure of charge, so that the force between two unit charges by coulomb's law gives 1/4p dynes, not 1 dyne.  This means that the relevant charge is 1/(2.sqrt pi) of the cgse.  
However, since hlu is a set of formulae based on three base units, (length, mass, time), it is possible to set these three independently, so one might have fps hlu or various atomic hlu.
The hlu are not simple multiples of the practical units, and never came into practical use.
Note also that there is a reference in Stephen Dresner ('Units of Measurement, An Encyclopaedic Dictionary') that refers to HLU, but actually constructs a mix of cm.g.s.Fr and cm.g.s.Bi, the units being out by various powers of 2sqrt(pi).  --Wendy.krieger (talk) 11:09, 7 January 2011 (UTC)
thread_title:  Heaviside-Lorentz is a system for forming units. 

message: Oliver Heaviside's "Electromagnetic Theory" appears to be the first text written in rationalised theory.  This is done by slight of hand, in that, for example, the flux D is equal to the displacement of charge, whereas the regular factor of 4pi is called for.  It also is one of the earliest references for using bold ('claredons') text for vectors, rather than fraktur font
Heaviside actually proposed a different set of rationalised units in "Electromagnetic Theory, Vol II" of 1899.  The discussion is page 275 et seq, basically suggests that the V, A, Ohm etc ought be replaced by new units, like a.V, A/a, a^2.Ohm etc.  Since these were still regarded as CGS extensions, further rationalisations were possible, such as eliminating different powers, and having variously 10^8 or 10^9 of the HLU.  The value of the magnetic constant is then 1e-9 H/cm.
There is correspondence between Heaviside and Giorgi http://www.iec.ch/about/history/documents/documents_giovanni.htm here.  This shows that Heaviside was rather dismayed that G was going to have mu=4pi E-7 H/m, particularly the 4pi factor.
The HLU in pretty much its modern form appears in Lorentz's work "The theory of Electrons" 1916 Teubner, Leipzig.  He credits Heaviside and Hertz with banishing the 4pi's by resizing the units.  (p2 op cit).  In any case, the book is certianly more readable to a modern reader than say Heaviside. 
Wendy.krieger (talk) 10:15, 27 September 2013 (UTC)
thread_title:  Some History 

message: The quantities "current" I and "current density" \mathbf{J} are listed in the wrong entry in the table. These quantities are in the "EMU" rather than the "ESU" category, so properly speaking the conversions should be:
I_{\mathrm{LH}} = \sqrt{4\pi}  I_{\mathrm{G}} = \sqrt{\mu_0} I_{\mathrm{SI}}
\mathbf{J}_{\mathrm{LH}} = \sqrt{4\pi} \mathbf{J}_{\mathrm{G}} = \sqrt{\mu_0} \mathbf{J}_{\mathrm{SI}}
This should place them in the same category as "magnetization" \mathbf{M} and "magnetic dipole moment" \mathbf{m}.  This is necessary for the following conversion to be true:
q_{\mathrm{SI}} = I_{\mathrm{SI}} t
q_{\mathrm{LH}} \sqrt{\epsilon_0} = I_{\mathrm{LH}}\frac{1}{\sqrt{\mu_0}}\ t
q_{\mathrm{LH}} = I_{\mathrm{LH}}\frac{1}{\sqrt{\mu_0\epsilon_0}}\ t
q_{\mathrm{LH}} = I_{\mathrm{LH}} c_0 t
This highlights the intrusion of c_0 into the relationship between current and charge, under LHU (and Gaussian).
Kodegadulo (talk) 22:11, 5 January 2017 (UTC)
thread_title:  Errors in Conversion Table 

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thread_title:  External links modified 

message: A number of articles exist that contain descriptions of Maxwell's equations (and thus have a table similar to the one containing the differential form of the equations here), but they all appeared slightly differently. I've begun collecting these tables in template pages that can be transcluded across all of these articles in an effort to homogenize things a little bit and make finding relevant information a little bit easier.
Glosser.ca (talk) 17:58, 14 August 2017 (UTC)
thread_title:  Consolidating Maxwell's equations 

message: The page says that  while simultaneously saying .
Rather than saying that LH units set  while also setting , wouldn't it be more accurate to say that  is set to , and similarly with Gaussian units setting ?
Ericvilas (talk) 09:09, 6 December 2019 (UTC)
replies: text: No, setting β = 1 / 4πε0 is wrong. The flux from a charge is Q/\beta = \Phi there is no \varepsilon in the formula.  The 4\pi = \gamma / \beta arises from the surface of the sphere vs the radius squared.  Wendy.krieger (talk) 10:16, 7 October 2022 (UTC)
thread_title:  Question regarding the value of {{math|1=''β''}} in CGS units 

message: , your claim that  would need a reliable source to warrant its inclusion here.  A simple falsification of your claim: Heaviside–Lorentz units are a form of metric system that does not rely for its definition of units on the size of any fundamental constant (with the arguable exception of the implicit use of the electric constant, whose only role is to eliminate the electromagnetic dimension).  The system of Planck units, and its variants, are all entirely premised on defining the unit sizes as products of powers of fundamental constants (in contrast, in the original Planck units system, the electromagnetic dimension is entirely ignored).  Since they have no commonality at the level of units whatsoever, the one cannot be a subtype of the other.  The only real commonality seems to be Heaviside's idea of "rationalization".
With your , it would seem to suggest that there might be a modified (rationalized) system of Planck units that is given the name "Lorentz–Heaviside Planck units", but notwithstanding the sharing of portions of the name, this does not make one an example of the other type, and particular, Heaviside–Lorentz units are most emphatically not "a type of Planck units".  I think you might have meant that "Heaviside–Lorentz Planck units are a variant of Planck units", which is not the same thing at all.  If you have a reliable source for "Lorentz–Heaviside Planck units" as currently described after your edits, this section would belong at Planck units, but in any event, it does not belong in this article.
If Lorentz–Heaviside Planck units are indeed notable (and as described, a more appropriate name would be "rationalized Planck units", which shows the weakness of the connection to this article), surely you should be able to source this?  I notice the complete lack of references for this section, and as such, it presents the appearance of original research being published in Wikipedia, which is not permitted.  If you can add reliable sources, I would encourage you to move this section to Planck units.  In any event, it is my considered opinion that this section has no place in this article.  —Quondum 11:33, 17 July 2020 (UTC)
replies: text: "Heaviside-Lorentz" doesn't just refer to CGS, but can describe any system with rationalized units, e.g. in Srednicki p.345, p.566, in professional physicists' vernacular. Being "natural" doesn't exclude a system from being "Heaviside-Lorentz," and such usage bears mention here. —wing gundam 00:25, 13 September 2020 (UTC)
thread_title:  "Heaviside-Lorentz units are also a type of Planck units"