Brightest flash ever recorded

Nowadays there are orbiting satellites that detect gamma rays. On
December 27th, 2004 they detected a flash. If this had been visible
light it would have lit up the entire sky more brightly than the full
moon. Some satellites were disabled and the Earth's atmosphere was
affected.

It turns out this flash, which lasted two tenths of a second, came
from a neutron star on the other side of our galaxy when the crust of
the star split open. The crust of the star was a mile thick and is
made of polymerized iron, which has a strength of well over a billion
times that of steel. Over time the magnetic field of the star builds
up inside of the star which eventually is able to completely crack
through a mile of polymerized iron and release all that energy.

http://www.space.com/1601-huge-quake-cracks-star.html

I wanted more detail. As best I could understand it is this. The
core of a neutron star produces a strong magnetic field. The core is
surrounded by a superconducting layer. Superconductors don't like
magnetic fields, but if the field is strong enough it forms a sort of
horizontal tornado in the superconductor that carries the magnetic
field. These tornadoes tend to grow, but are blocked by the
superstrong iron crust. The crust is also a superconductor so it
doesn't want the magnetic field either, but is too stiff and tough for
the atoms to move so a tornado can't form in the crust. Basically you
have the strongest magnet in the universe contained by the strongest
iron in the universe. In some neutron stars the magnetic force of the
tornado eventually builds up enough to fracture the crust, the tornado
escapes, and its energy is released. Kaboom!

The crust vibrated like a bell when the crack opened. I would think
this the loudest sound possible in this Universe. The width of the
crack vibrated at that frequency, so also did the intensity of the
gamma rays, and the pitch could be measured exactly. It was 100
cycles a second, about the same pitch as the lowest note on a guitar.

The same sort of thing happens on the Sun. Tornadoes, aka flux tubes,
form in the material of the sun and tend to grow. The tube of the
tornado forms an arch, and the two ends of the arch are seen as a pair
of sunspots. As the arch grows the sunspots move further apart.
Eventually the arch may blow off of the sun as a solar flare. In high
school they showed us a movie of a solar flare with a diameter equal
to that of the sun itself. Here's a spectacular video of an M-class
flare. http://www.youtube.com/watch?v=RnJBTmaRURU There is an X
class which is even larger.

On 06/02/2011 03:55 AM, Frisbieinstein wrote:
http://www.space.com/1601-huge-quake-cracks-star.html

I wanted more detail. As best I could understand it is this. The
core of a neutron star produces a strong magnetic field. The core is
surrounded by a superconducting layer. Superconductors don't like
magnetic fields, but if the field is strong enough it forms a sort of
horizontal tornado in the superconductor that carries the magnetic
field. These tornadoes tend to grow, but are blocked by the
superstrong iron crust. The crust is also a superconductor so it
doesn't want the magnetic field either, but is too stiff and tough for
the atoms to move so a tornado can't form in the crust. Basically you
have the strongest magnet in the universe contained by the strongest
iron in the universe. In some neutron stars the magnetic force of the
tornado eventually builds up enough to fracture the crust, the tornado
escapes, and its energy is released. Kaboom!

Now, the core of a neutron star is obviously made of neutronium -- i.e.
the material so dense that electrons get crushed into protons and then
get turned into neutrons! I don't think that stuff would be conductive,
let alone superconductive: electrons can't pass through that.

Now as for the crust of the neutron star, that's made of white dwarf
star material. Specifically, iron white dwarf star material, the densest
of all white dwarf star materials -- just one step below neutronium in
density. As such, even though it's unimaginably dense compared to any
materials we have on Earth, it is still softer than neutronium which is
even more dense. So when it comes to a contest of strength between white
dwarf material and neutronium, neutronium will always win out.

Regarding whether regions of a neutron star are superconductive, they
may be, but I don't think it's necessarily the case. But even if it were
superconductive, where do you get the idea that superconductors don't
like magnetic fields? Superconductors produce their own magnetic fields,
just by the classical laws of electromagnetism they must produce
magnetic fields as electricity flows through a material. Now
superconductors on Earth may not like external magnetic fields, because
they might affect their superconductivity, but their own magnetic fields
are fine. Near a neutron star, there is no stronger magnetic field than
that of the neutron star itself, so there is no magnetic field that can
affect its superconductivity.

All that stuff about tornados and stuff, I don't think it has anything
to do with reality. A tornado implies to me a very localized area of
torsional strain. A magnetic field isn't that localized, it twists and
turns around the entire neutron star. If it creates a break in a certain
portion of the neutron star's crust, then that was likely the weakest
part of the crust, but the strain would've affected all parts of the
crust equally more or less.

Local variations of magnetic fields are caused by competing magnetic
fields. They'll either work to reduce the local magnetic field, or work
to weaken it.

Yousuf Khan

On Jun 9, 7:14*am, Yousuf Khan wrote:
On 06/02/2011 03:55 AM, Frisbieinstein wrote:

http://www.space.com/1601-huge-quake-cracks-star.html

I wanted more detail. *As best I could understand it is this. *The
core of a neutron star produces a strong magnetic field. *The core is
surrounded by a superconducting layer. *Superconductors don't like
magnetic fields, but if the field is strong enough it forms a sort of
horizontal tornado in the superconductor that carries the magnetic
field. *These tornadoes tend to grow, but are blocked by the
superstrong iron crust. *The crust is also a superconductor so it
doesn't want the magnetic field either, but is too stiff and tough for
the atoms to move so a tornado can't form in the crust. *Basically you
have the strongest magnet in the universe contained by the strongest
iron in the universe. *In some neutron stars the magnetic force of the
tornado eventually builds up enough to fracture the crust, the tornado
escapes, and its energy is released. *Kaboom!

Now, the core of a neutron star is obviously made of neutronium -- i.e.
the material so dense that electrons get crushed into protons and then
get turned into neutrons! I don't think that stuff would be conductive,
let alone superconductive: electrons can't pass through that.

Now as for the crust of the neutron star, that's made of white dwarf
star material. Specifically, iron white dwarf star material, the densest
of all white dwarf star materials -- just one step below neutronium in
density. As such, even though it's unimaginably dense compared to any
materials we have on Earth, it is still softer than neutronium which is
even more dense. So when it comes to a contest of strength between white
dwarf material and neutronium, neutronium will always win out.

Regarding whether regions of a neutron star are superconductive, they
may be, but I don't think it's necessarily the case. But even if it were
superconductive, where do you get the idea that superconductors don't
like magnetic fields? Superconductors produce their own magnetic fields,
just by the classical laws of electromagnetism they must produce
magnetic fields as electricity flows through a material. Now
superconductors on Earth may not like external magnetic fields, because
they might affect their superconductivity, but their own magnetic fields
are fine. Near a neutron star, there is no stronger magnetic field than
that of the neutron star itself, so there is no magnetic field that can
affect its superconductivity.

All that stuff about tornados and stuff, I don't think it has anything
to do with reality. A tornado implies to me a very localized area of
torsional strain. A magnetic field isn't that localized, it twists and
turns around the entire neutron star. If it creates a break in a certain
portion of the neutron star's crust, then that was likely the weakest
part of the crust, but the strain would've affected all parts of the
crust equally more or less.

Local variations of magnetic fields are caused by competing magnetic
fields. They'll either work to reduce the local magnetic field, or work
to weaken it.

* * * * Yousuf Khan

I of course have no idea, but the experts seem to be saying that
neutron star cores are superconductive and that this is confirmed by
experimental evidence.

http://www.ualberta.ca/~heinke/CasA/Cooling.html

On 11/06/2011 6:13 AM, Frisbieinstein wrote:
I of course have no idea, but the experts seem to be saying that
neutron star cores are superconductive and that this is confirmed by
experimental evidence.

http://www.ualberta.ca/~heinke/CasA/Cooling.html

According to that link, the only place where superconductivity will
exist is in the protons:

" When two neutrons pair up, they fall into a lower-energy state. The
extra energy is released as neutrinos, which easily escape from the
neutron star into space. Thus the pairing of neutrons rapidly cools the
neutron star. Neutron pairs may be broken (by being "bumped" by other
neutrons), and re-form; every time a pair forms, neutrinos are emitted.
This cooling by pair formation can only happen when the neutron star
interior is cool enough to become a superfluid. The Page and Shternin
groups are able to explain the rapid neutron star cooling by saying that
the neutrons have only recently become superfluid--giving a superfluid
transition temperature of 0.5-1 billion degrees K. They also need proton
superconductivity to exist in the neutron star, in order to suppress
other cooling mechanisms until neutron pair formation starts the rapid
cooling. "
http://www.ualberta.ca/~heinke/CasA/Cooling.html

So the superfluidity of the neutrons have nothing to do with
superconductivity, just of the protons.

Yousuf Khan

On Jun 13, 12:59*pm, Yousuf Khan wrote:
On 11/06/2011 6:13 AM, Frisbieinstein wrote:

I of course have no idea, but the experts seem to be saying that
neutron star cores are superconductive and that this is confirmed by
experimental evidence.

http://www.ualberta.ca/~heinke/CasA/Cooling.html

According to that link, the only place where superconductivity will
exist is in the protons:

" When two neutrons pair up, they fall into a lower-energy state. The
extra energy is released as neutrinos, which easily escape from the
neutron star into space. Thus the pairing of neutrons rapidly cools the
neutron star. Neutron pairs may be broken (by being "bumped" by other
neutrons), and re-form; every time a pair forms, neutrinos are emitted.
This cooling by pair formation can only happen when the neutron star
interior is cool enough to become a superfluid. The Page and Shternin
groups are able to explain the rapid neutron star cooling by saying that
the neutrons have only recently become superfluid--giving a superfluid
transition temperature of 0.5-1 billion degrees K. They also need proton
superconductivity to exist in the neutron star, in order to suppress
other cooling mechanisms until neutron pair formation starts the rapid
cooling. "http://www.ualberta.ca/~heinke/CasA/Cooling.html

So the superfluidity of the neutrons have nothing to do with
superconductivity, just of the protons.

* * * * Yousuf Khan

Right. But what I have been told is that the neutrons have enough
beta decay to also be a superconductor. I haven't gotten around to
doing a calculation -- it would probably be wrong anyway -- but my
guess is that there is enough beta decay to make the entire core
superconductive. There isn't much, but the material is so extremely
dense that even if a very small percentage of charged particles are
available, in absolute terms it could be enough.

I first came across this when I was told that the rotating superfluid
neutrons generate a strong magnetic field. That was a surprise.

On 13/06/2011 11:17 AM, Frisbieinstein wrote:
Right. But what I have been told is that the neutrons have enough
beta decay to also be a superconductor. I haven't gotten around to
doing a calculation -- it would probably be wrong anyway -- but my
guess is that there is enough beta decay to make the entire core
superconductive. There isn't much, but the material is so extremely
dense that even if a very small percentage of charged particles are
available, in absolute terms it could be enough.

I first came across this when I was told that the rotating superfluid
neutrons generate a strong magnetic field. That was a surprise.

I'd say at the edges of the neutronium you'd actually get escape of the
electrons, but anywhere down towards the centre you'll get the electron
getting recaptured. So if there is going to be any conductivity, it'll
have to be the border region between the neutronium and the dwarf star
material.

Yousuf Khan

On Jun 16, 5:26*am, Yousuf Khan wrote:
On 13/06/2011 11:17 AM, Frisbieinstein wrote:

Right. *But what I have been told is that the neutrons have enough
beta decay to also be a superconductor. *I haven't gotten around to
doing a calculation -- it would probably be wrong anyway -- but my
guess is that there is enough beta decay to make the entire core
superconductive. *There isn't much, but the material is so extremely
dense that even if a very small percentage of charged particles are
available, in absolute terms it could be enough.

I first came across this when I was told that the rotating superfluid
neutrons generate a strong magnetic field. *That was a surprise.

I'd say at the edges of the neutronium you'd actually get escape of the
electrons, but anywhere down towards the centre you'll get the electron
getting recaptured. So if there is going to be any conductivity, it'll
have to be the border region between the neutronium and the dwarf star
material.

* * * * Yousuf Khan

THE ASTROPHYSICAL JOURNAL, 492:267–280, 1998 January 1
© 1998. The American Astronomical Society. All rights reserved.
Printed in U.S.A.
Neutron Star Magnetic Field Evolution, Crust Movement, and Glitches
MALVIN RUDERMAN TIANHUA ZHU, AND KAIYOU CHEN
Physics Department and Columbia Astrophysics Laboratory, Columbia
University, 538 West 120th Street, New York, NY 10027
Received 1997 April 25; accepted 1997 August 13

In a type II superconductor, expected to be present below the crust
and perhaps all the way down to the central core,

----

So that's a definite maybe.

On Jun 9, 9:14Â*pm, Yousuf Khan wrote:
On 06/02/2011 03:55 AM, Frisbieinstein wrote:

http://www.space.com/1601-huge-quake-cracks-star.html



All that stuff about tornados and stuff, I don't think it has anything
to do with reality. A tornado implies to me a very localized area of
torsional strain. A magnetic field isn't that localized, it twists and
turns around the entire neutron star. If it creates a break in a certain
portion of the neutron star's crust, then that was likely the weakest
part of the crust, but the strain would've affected all parts of the
crust equally more or less.

THE ASTROPHYSICAL JOURNAL, 492:267–280, 1998 January 1
© 1998. The American Astronomical Society. All rights reserved.
Printed in U.S.A.
Neutron Star Magnetic Field Evolution, Crust Movement, and Glitches
MALVIN RUDERMAN TIANHUA ZHU, AND KAIYOU CHEN
Physics Department and Columbia Astrophysics Laboratory, Columbia
University, 538 West 120th Street, New York, NY 10027
Received 1997 April 25; accepted 1997 August 13

A spinning-down (spinning-up) neutron star's neutron superfluid vortex
array must expand (contract). Because the core of a neutron vortex and
a flux tube interact strongly as they pass through each other, the
moving vortices will push on the proton's flux-tube array (Sauls 1989;
Srinivasan et al. 1990; Ruderman 1991a, 1991b), forcing it either (a)
to move together with the vortices or (b) to be cut through if the
flux-tube array cannot respond fast enough to take part in the vortex
motion. Section 2 discusses possible relationships among a pulsar's Ω,
B, and rate of change of spin ($\mathstrut{{\ucpmathaccent{{\Omega}}
{), which discriminate between these two behaviors. In case a the
evolution of the magnetic field at the core-crust interface is well
determined by the initial magnetic field configuration and subsequent
changes in stellar Ω. In case b the core-crust interface field would
evolve more slowly relative to changes in Ω, although qualitative
features of the evolution should be similar to those of case a. Some
microphysics and observations, considered in §§ 2 and 3, support case
a behavior for pulsars whose spin-down (or spin-up) ages, T$
\mathstrut{_{s}}$=| Ω/2$\mathstrut{{\ucpmathaccent{{\Omega}}{ |, are
not less than those of Vela-like radio pulsars (Ts ∼ 104 yr) and case
b behavior for the much more rapidly spinning-down Crab-like radio
pulsars (Ts ∼ 103 yr).

Between the stellar core and the world outside it there is a
solid crust with a very high electrical conductivity. If the crust
were absolutely rigid and a perfect conductor, then its response to
changes in the core magnetic field would be limited to rigid crust
rotations. Of course neither is the case.

A high density of core flux tubes merges into a smooth field when
passing through the crust. Because of the almost rigid crust's high
conductivity, it, at least temporarily, freezes in place the capitals
of the core's flux tubes. As these flux tube capitals at the crust-
core interface are pushed by a moving core neutron vortex array, a
large stress builds up in the crust. This stress will be relaxed when
the crust is stressed beyond its yield strength, or, if the buildup is
slow enough, by dissipation of the crustal eddy currents that hold the
magnetic field in place as it passes from the core through the crust.
The shear modulus of a crust is well described quantitatively,

----

The crustal cracking has to do with the magnetic field of the core.
The flux tubes freeze to the crust, then are pushed by the superfluid
vortices. The crust may shear.

By the way, studies of precessing neutron stars indicate that the
vortices are not pinned in such stars. If they were, the star would
precess much faster.