Editing Magnetic field (section)

=== The H-field ===

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!Alternative names for '''H'''<ref name=Electromagnetics />
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* Magnetic field intensity<ref name=Stratton>{{cite book|title=Electromagnetic Theory|first=Julius Adams|last=Stratton|year=1941|publisher=McGraw-Hill|page=1|isbn=978-0070621503|edition=1st}}</ref>
* Magnetic field strength<ref name=":1"/>{{rp|p=139}}
* Magnetic field
* Magnetizing field
* Auxiliary magnetic field
|}

The magnetic {{math|'''H'''}} field is defined:<ref name="Griffiths3ed"/>{{rp|p=269}}<ref name="jackson3ed"/>{{rp|p=192}}<ref name="feynman" />{{Rp|at=ch36}}

{{Equation box 1
|indent=:
|title='''Definition of the {{math|H}} field''' ''([[Euclidean vector|vector]] form, [[International System of Units|SI units]])''
|equation=<math>\mathbf{H}\equiv\frac{1}{\mu_0}\mathbf{B}-\mathbf{M}</math>
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|border colour = rgb(0,115,207)
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where <math>\mu_0</math> is the [[vacuum permeability]], and {{math|'''M'''}} is the [[Magnetization|magnetization vector]]. In a vacuum, {{math|'''B'''}} and {{math|'''H'''}} are proportional to each other. Inside a material they are different (see [[#H-field and magnetic materials|H and B inside and outside magnetic materials]]). The SI unit of the {{math|'''H'''}}-field is the [[ampere]] per metre (A/m),<ref>{{cite web|title=International system of units (SI) |url=http://physics.nist.gov/cuu/Units/units.html |website=NIST reference on constants, units, and uncertainty |date=12 April 2010 |publisher=National Institute of Standards and Technology |access-date=9 May 2012}}</ref> and the CGS unit is the [[oersted]] (Oe).<ref name=BIPMTab9/><ref name="purcell2ed"/>{{rp|p=286|quote= Units: Tesla for describing a large magnetic force; gauss (tesla/10000) for describing a small magnetic force as that at the surface of earth.}}