The Reissner-Nordstrom metric

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In summary: Q(r) = \frac{1}{r^2} \int_0^r 4 \pi r^2 \rho_{ch} e^{\frac{\lambda}{2}} drWhat is the electric system charge?Q(r) = \frac{1}{r^2} \int_0^r 4 \pi r^2 \rho_{ch} e^{\frac{\lambda}{2}} dr
  • #1
Orion1
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Two citations referenced by Wikipedia with respect to General Relativity models for spinless charged neutron stars, reference 2 - eq. 24, states that the Reissner-Nordstrom metric relativistic Einstein-Maxwell Gauss law for the electric system charge is:
[tex]Q(r) = \int_0^r 4 \pi j^0 e^{\frac{(\nu + \lambda)}{2}} dr[/tex]

However, according to reference 3 - eq. 5, the electric system charge is:
[tex]Q(r) = \frac{1}{r^2} \int_0^r 4 \pi r^2 \rho_{ch} e^{\frac{\lambda}{2}} dr[/tex]

What Einstein-Maxwell charge effects with respect to the metric components [tex]\nu[/tex] and [tex]\lambda[/tex] are these equations describing?

Why does the reference 2 equation have two metric components and the reference 3 equation has only one metric component?

Why is the reference 2 equation missing the [tex]r^2[/tex] dimensions?

And what are the International System of Units (S.I.) for [tex]j^0[/tex] and [tex]\rho_{ch}[/tex]?

Please post links to this thread for subject equations cross-reference.

Reference:
http://en.wikipedia.org/wiki/Reissner%E2%80%93Nordstr%C3%B6m_metric"
http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.2708v2.pdf"
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332004000200038"
 
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  • #2
total mass of charged neutron star...


How was this equation generated?

Total mass of spinless charged neutron star at a radial distance r:
[tex]\frac{dm(r)}{dr} = \frac{4 \pi r^2 \epsilon(r)}{c^2} + \frac{Q(r)}{c^2 r} \frac{dQ(r)}{dr}[/tex]

How exactly does charge contribute to mass this way?

Reference:
http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.2708v2.pdf"
 
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  • #3

Please post links to this thread for subject equations cross-reference.
 
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  • #4
nu metric component...



Given that [tex]F^{\mu \kappa}[/tex] satifies the covariant Maxwell field equation:
[tex]\left[\sqrt{-g} F^{\kappa \mu} \right]_{, \mu} = 4 \pi J^{\kappa} \sqrt{-g}[/tex]

The quantity [tex]J^{\kappa}[/tex] denotes the four-current which represents the electromagnetic sources in the star. For a static spherically symmetric system, the only non-zero component of the four-current is [tex]J^1[/tex], which implies that the only non-vanishing component of [tex]F^{\kappa \mu}[/tex] is [tex]F^{01}[/tex]:

In this case I derived this formula for the relativistic electric field:
[tex]F^{01}(r) = E(r) = \frac{Q(r)}{r^2} e^{- \frac{ \left( \nu + \lambda \right)}{2}}[/tex]

The formula suggested by the remaining reference papers:
[tex]F^{01}(r) = E(r) = \frac{Q(r)}{r^2}[/tex]

Electric system charge:
[tex]Q(r) = \int_0^r 4 \pi j^0 e^{\frac{ \left( \nu + \lambda \right)}{2}} dr[/tex]

The formula suggested by the remaining reference papers:
[tex]Q(r) = \int_0^r 4 \pi r^2 \rho_{ch} e^{\frac{\lambda}{2}} dr[/tex]

Therefore:
[tex]\boxed{j^0 = \rho_{ch} r^2}[/tex]

Integration by substitution:
[tex]F^{01}(r) = E(r) = \frac{e^{- \frac{ \left( \nu + \lambda \right)}{2}}}{r^2} \int_0^r 4 \pi j^0 e^{\frac{ \left( \nu + \lambda \right)}{2}} dr[/tex]

Why does this solution have a [tex]\nu[/tex] metric component and two metric components relativistic electric_field modifier [tex]e^{- \frac{ \left( \nu + \lambda \right)}{2}}[/tex]?

Reference:
http://en.wikipedia.org/wiki/Reissner%E2%80%93Nordstr%C3%B6m_metric"
http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.2708v2.pdf"
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332004000200038"
http://www.google.com/url?sa=t&sour...o.pdf&usg=AFQjCNG7gtMPDuwpTrqYwoZ2NuS1lk1nRw"
 
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1. What is the Reissner-Nordstrom metric?

The Reissner-Nordstrom metric is a mathematical equation that describes the geometry of spacetime in the presence of a charged, non-rotating black hole. It is a solution to Einstein's equations of general relativity and is named after Hans Reissner and Gunnar Nordstrom, who independently discovered it in the early 20th century.

2. How does the Reissner-Nordstrom metric differ from the Schwarzschild metric?

The Reissner-Nordstrom metric includes an additional term for the electric charge of the black hole, whereas the Schwarzschild metric describes an uncharged black hole. This means that the Reissner-Nordstrom metric can only be applied to charged black holes, while the Schwarzschild metric can be used for both charged and uncharged black holes.

3. What is the significance of the event horizon in the Reissner-Nordstrom metric?

The event horizon in the Reissner-Nordstrom metric is the boundary beyond which light cannot escape the gravitational pull of the black hole. For a charged black hole, the event horizon is located at a larger radius compared to an uncharged black hole of the same mass, due to the repulsive force of the electric charge.

4. Does the Reissner-Nordstrom metric have any physical implications?

Yes, the Reissner-Nordstrom metric has important implications for the behavior of charged black holes. It predicts that charged black holes can have a singularity (a point of infinite density) surrounded by a second, larger event horizon. It also predicts that charged black holes can have a "naked singularity," meaning that the singularity is not hidden behind an event horizon. However, this is still a subject of debate among physicists.

5. How is the Reissner-Nordstrom metric used in astrophysics?

The Reissner-Nordstrom metric is used in astrophysics to study the behavior of charged black holes and their effects on the surrounding spacetime. It is also used in the study of electromagnetic radiation from black holes, such as the jets of particles that are emitted from black holes with strong magnetic fields. Additionally, the Reissner-Nordstrom metric is used in theoretical models and simulations to understand the formation and evolution of charged black holes in the universe.

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