<p>The solar wind is just a stream of charged particles, mostly protons and electrons, some alpha particles and a tiny trace amount of other stuff.    </p>

<p>If the solar wind approached an uncharged Neutron star, then the particles would simply fall onto the neutron star or circle around it in a hyperbolic orbit.  The Neutron star's gravity would add considerable velocity to the particles due to it's strong gravity.   Any particle that falls within about 2 radii of the neutron star would inevitably fall towards it due to the space-time properties of relativistic orbits, so there would be some spiraling in and probably some kind of light-show in the process.  The impacts of particles onto the surface would likely be in the x-ray or gamma ray spectrums and might not be that visible.   Ultimately it wouldn't be that interesting, but perhaps there would be some kind of light-show.</p>

<p>If we give the Neutron star a strong magnetic field, then the solar wind would simply get redirected, similar to how it gets redirected by Earth's magnetic field, except in this case, the magnetic field is much stronger and the central object, much smaller.  Probably very few of the solar wind particles would hit the Neutron star and most would just circle around it's magnetic field, which would produce (I think) less of a light show.   There wouldn't be much effect that I can think of.  The Magnetar star is very massive with a very strong magnetic field.  The solar wind is comparatively, especially after spreading out for 93 million miles, quite diffuse and weak.</p>

<p>If a person got hit directly by the solar wind, it might be deadly.   We're not very tough, but a magnetar is one of the most indestructible objects in the universe.   The effect would be negligible.   </p>

<p>It might be more interesting if you moved the Magnetar much closer to the star.   Magnetic field lines can't cross each other, but they can push each other and flatten out, and in the case of solar flares they can get very twisted (but still never cross).   </p>

<p>A magnetar is several orders of magnitude smaller than a sunspot.   The interaction between the two magnetic fields, if the magnetar passed close to a sunspot would be interesting to see. (though the gravitational effect would still probably be the more impressive of the two)  But if you move a Magnetar as distant as the Earth, the solar wind would have lost much of it's strength and it would just be ejected material from a solar magnetic storm.  It wouldn't have much effect on the magnetar.   </p>

<p>That's my hobbyist understanding anyway.   If I missed any key points, please clarify your question or ask a new question.</p>

CC BY-SA 4.0
2019-07-06T07:38:58.830Z
2019-07-06T07:38:58.830Z
userLTK
<p>First, <a href="https://en.wikipedia.org/wiki/Magnetar" rel="nofollow noreferrer">magnetars</a> are absolutely bizarre objects with magnetic fields so strong the rotation of the object can result in <a href="https://en.wikipedia.org/wiki/Pair_production" rel="nofollow noreferrer">pair production</a> in a vacuum.</p>
<p>So perhaps the two most important things that the <a href="https://en.wikipedia.org/wiki/Solar_wind" rel="nofollow noreferrer">solar wind</a> will do are form a <a href="https://en.wikipedia.org/wiki/Bow_shock" rel="nofollow noreferrer">bow shock</a> and drive <a href="https://en.wikipedia.org/wiki/Magnetic_reconnection" rel="nofollow noreferrer">magnetic reconnection</a>.  All gas near a magnetar is going to be a <a href="https://en.wikipedia.org/wiki/Plasma_(physics)" rel="nofollow noreferrer">plasma</a>.  However, magnetars are usually surrounded by a pair plasma (i.e., positrons and electrons only) but the solar wind is comprised of mostly electrons, protons, and alpha-particles (ordered by number density from highest to lowest).</p>
<p>All of the above is kind of boring in the sense that it's expected and well known.  What would be interesting, however, is to see what the standoff distance of the bow shock would be given how strong the <a href="https://en.wikipedia.org/wiki/Magnetic_moment" rel="nofollow noreferrer">magnetic moment</a> of a magnetar can be.</p>
<p>There is an approximate analytical expression for the standoff distance of the <a href="https://en.wikipedia.org/wiki/Magnetopause" rel="nofollow noreferrer">magnetopause</a>, which is just the balance of ram and magnetic pressure, given by:
<span class="math-container">$$
r_{ss} = \left( \frac{ \mu_{o} \ \lvert \mathbf{m} \rvert^{2} }{ \pi^{2} \ \rho_{sw} V_{sw}^{2} } \right)^{1/6} \tag{0}
$$</span>
where <span class="math-container">$\rho_{sw}$</span> is the mass density [kg m<sup>-3</sup>] of the solar wind, <span class="math-container">$V_{sw}$</span> is the bulk flow speed [m/s] of the solar wind, <span class="math-container">$\mu_{o}$</span> is the <a href="https://en.wikipedia.org/wiki/Permeability_(electromagnetism)" rel="nofollow noreferrer">permeability</a> of free space [N A<sup>-2</sup>], <span class="math-container">$r_{ss}$</span> is the subsolar standoff distance of the magnetopause [m], and <span class="math-container">$\mathbf{m}$</span> is the magnetic dipole moment [A m<sup>2</sup>] of the source object.</p>
<p>Note that the magnetic moment of a dipole magnet can be approximated as:
<span class="math-container">$$
\lvert \mathbf{m} \rvert \approx \frac{ 2 \ \pi \ r^{3} }{ \mu_{o} } \lvert \mathbf{B} \rvert \tag{1}
$$</span>
where <span class="math-container">$\mathbf{B}$</span> is the magnetic field [T] vector.</p>
<p>Magnetars have <span class="math-container">$B_{o}$</span> ~ 10<sup>9</sup> – 10<sup>11</sup> T and radii of ~20 km, thus their magnetic moments are <span class="math-container">$\lvert \mathbf{m} \rvert$</span> ~ 10<sup>28</sup> – 10<sup>30</sup> A m<sup>2</sup>.  For comparison, Jupiter has the largest <a href="https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter" rel="nofollow noreferrer">magnetic field</a> strength of all planetary bodies in the solar system, with a magnetic moment of ~10<sup>27</sup> A m<sup>2</sup> [e.g., see <a href="https://doi.org/10.1016/j.pss.2009.06.024" rel="nofollow noreferrer"><em>Durand-Manterola</em>, 2009</a>].  Note that the mean equatorial Jovian radius is ~3575 times larger than a magnetar.</p>
<p>Typical solar wind values near Earth are <span class="math-container">$\rho_{sw}$</span> ~ 1.673 x 10<sup>-20</sup> kg m<sup>-3</sup> and <span class="math-container">$V_{sw}$</span> ~ 4 x 10<sup>5</sup> m/s [e.g., see <a href="https://doi.org/10.1029/2020RG000714" rel="nofollow noreferrer"><em>Wilson et al.</em>, 2021</a>].  The magnitude of <span class="math-container">$V_{sw}$</span> stays constant out past Jupiter but <span class="math-container">$\rho_{sw}$</span> ~ r<sup>-2</sup>, thus the mass density should be roughly 25 times lower at Jupiter than Earth (which it usually is).</p>
<p>Solving Equation 0 using these values we find that for a magnetar we have <span class="math-container">$r_{ss}$</span> ~ 3–15 x 10<sup>5</sup> <span class="math-container">$R_{Mag}$</span> (where <span class="math-container">$R_{Mag}$</span> is the magnetar radius) and for Jupiter <span class="math-container">$r_{ss}$</span> ~ 52 <span class="math-container">$R_{J}$</span> (where <span class="math-container">$R_{J}$</span> ~ 71492 km is the mean Jovian equatorial radius), which is close to the observed value.  For comparison, Earth has <span class="math-container">$\lvert \mathbf{m} \rvert$</span> ~ 8 x 10<sup>22</sup> A m<sup>2</sup>, which corresponds to <span class="math-container">$r_{ss}$</span> ~ 12 <span class="math-container">$R_{E}$</span> (where <span class="math-container">$R_{E}$</span> ~ 6378 km is the mean Earth equatorial radius).  If we normalize the magnetar magnetopause <span class="math-container">$r_{ss}$</span> by <span class="math-container">$R_{J}$</span>, we get a range of ~91–423, i.e., ~2-8 times larger than the Jovian magnetosphere (which is the largest natural, identifiable system within the heliosphere).</p>

CC BY-SA 4.0
2022-10-14T15:34:21.197Z
2022-10-14T18:26:57.267Z
2022-10-14T18:26:57.267Z
honeste_vivere
<p>As we know magnetars have strong magnetic field but what if we swap earth with a magnetar and the sun will released a solar wind. Is the magnetar affected by the solar wind or not ? </p>

CC BY-SA 4.0
2019-07-03T02:40:16.313Z
As a side-bar, if you put a magnetar where Earth is, you've just broken the solar-system.    One star systems can have planets in neat little orbits around the star, but tight binary systems can't.   The 7 remaining planets would get tossed about willy nilly in the gravitational chaos that would ensue.
userLTK
CC BY-SA 4.0
2019-07-03T04:29:34.350Z
What userLTK said. On this site, we like questions to be about actual (or possible) astronomical phenomena. So how about changing your question to be about a magnetar in a binary system with a Sun-like companion, orbiting each other at a distance of 1 AU (the distance from the Sun to the Earth)?
PM 2Ring
CC BY-SA 4.0
2019-07-03T08:32:34.970Z
A magnetar would have a huge effect on the solar wind. And a normal magnetar has a large amount of gas near it, left over from the recent supernova explosion that created the magnetar.
PM 2Ring
CC BY-SA 4.0
2019-07-03T21:36:23.700Z
I don't think the magnetar will be much affected by the solar wind. The solar wind is too diffuse and feeble to do much. Close in the energy stored in a magnetars magnetic field is 1000 times as dense as lead. The solar wind (and indeed the sun, as well as all the planets) will be pretty violently affected by the magnetar.
Steve Linton
<the-sun><magnetic-field><solar-wind>
The sun's SOLAR WIND VS MAGNETAR
SpaceCenterMars
# The sun's SOLAR WIND VS MAGNETAR

(Asked by: username_0 on 2019-07-03)

As we know magnetars have strong magnetic field but what if we swap earth with a magnetar and the sun will released a solar wind. Is the magnetar affected by the solar wind or not ?

**Tags:** the-sun, magnetic-field, solar-wind
> **Comments:**
> **username_1**: As a side-bar, if you put a magnetar where Earth is, you've just broken the solar-system.    One star systems can have planets in neat little orbits around the star, but tight binary systems can't.   The 7 remaining planets would get tossed about willy nilly in the gravitational chaos that would ensue.  
> **username_2**: What userLTK said. On this site, we like questions to be about actual (or possible) astronomical phenomena. So how about changing your question to be about a magnetar in a binary system with a Sun-like companion, orbiting each other at a distance of 1 AU (the distance from the Sun to the Earth)?  
> **username_2**: A magnetar would have a huge effect on the solar wind. And a normal magnetar has a large amount of gas near it, left over from the recent supernova explosion that created the magnetar.  
> **username_3**: I don't think the magnetar will be much affected by the solar wind. The solar wind is too diffuse and feeble to do much. Close in the energy stored in a magnetars magnetic field is 1000 times as dense as lead. The solar wind (and indeed the sun, as well as all the planets) will be pretty violently affected by the magnetar.  

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## 2 answers

### Answer by username_1 on 2019-07-06. Score: 1 | Accepted answer

The solar wind is just a stream of charged particles, mostly protons and electrons, some alpha particles and a tiny trace amount of other stuff.

If the solar wind approached an uncharged Neutron star, then the particles would simply fall onto the neutron star or circle around it in a hyperbolic orbit. The Neutron star's gravity would add considerable velocity to the particles due to it's strong gravity. Any particle that falls within about 2 radii of the neutron star would inevitably fall towards it due to the space-time properties of relativistic orbits, so there would be some spiraling in and probably some kind of light-show in the process. The impacts of particles onto the surface would likely be in the x-ray or gamma ray spectrums and might not be that visible. Ultimately it wouldn't be that interesting, but perhaps there would be some kind of light-show.

If we give the Neutron star a strong magnetic field, then the solar wind would simply get redirected, similar to how it gets redirected by Earth's magnetic field, except in this case, the magnetic field is much stronger and the central object, much smaller. Probably very few of the solar wind particles would hit the Neutron star and most would just circle around it's magnetic field, which would produce (I think) less of a light show. There wouldn't be much effect that I can think of. The Magnetar star is very massive with a very strong magnetic field. The solar wind is comparatively, especially after spreading out for 93 million miles, quite diffuse and weak.

If a person got hit directly by the solar wind, it might be deadly. We're not very tough, but a magnetar is one of the most indestructible objects in the universe. The effect would be negligible.

It might be more interesting if you moved the Magnetar much closer to the star. Magnetic field lines can't cross each other, but they can push each other and flatten out, and in the case of solar flares they can get very twisted (but still never cross).

A magnetar is several orders of magnitude smaller than a sunspot. The interaction between the two magnetic fields, if the magnetar passed close to a sunspot would be interesting to see. (though the gravitational effect would still probably be the more impressive of the two) But if you move a Magnetar as distant as the Earth, the solar wind would have lost much of it's strength and it would just be ejected material from a solar magnetic storm. It wouldn't have much effect on the magnetar.

That's my hobbyist understanding anyway. If I missed any key points, please clarify your question or ask a new question.


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### Answer by username_4 on 2022-10-14. Score: 4

First, [magnetars](https://en.wikipedia.org/wiki/Magnetar) are absolutely bizarre objects with magnetic fields so strong the rotation of the object can result in [pair production](https://en.wikipedia.org/wiki/Pair_production) in a vacuum.

So perhaps the two most important things that the [solar wind](https://en.wikipedia.org/wiki/Solar_wind) will do are form a [bow shock](https://en.wikipedia.org/wiki/Bow_shock) and drive [magnetic reconnection](https://en.wikipedia.org/wiki/Magnetic_reconnection). All gas near a magnetar is going to be a [plasma](https://en.wikipedia.org/wiki/Plasma_(physics)). However, magnetars are usually surrounded by a pair plasma (i.e., positrons and electrons only) but the solar wind is comprised of mostly electrons, protons, and alpha-particles (ordered by number density from highest to lowest).

All of the above is kind of boring in the sense that it's expected and well known. What would be interesting, however, is to see what the standoff distance of the bow shock would be given how strong the [magnetic moment](https://en.wikipedia.org/wiki/Magnetic_moment) of a magnetar can be.

There is an approximate analytical expression for the standoff distance of the [magnetopause](https://en.wikipedia.org/wiki/Magnetopause), which is just the balance of ram and magnetic pressure, given by:
$$
r\_{ss} = \left( \frac{ \mu\_{o} \ \lvert \mathbf{m} \rvert^{2} }{ \pi^{2} \ \rho\_{sw} V\_{sw}^{2} } \right)^{1/6} \tag{0}
$$
where $\rho\_{sw}$ is the mass density [kg m-3] of the solar wind, $V\_{sw}$ is the bulk flow speed [m/s] of the solar wind, $\mu\_{o}$ is the [permeability](https://en.wikipedia.org/wiki/Permeability_(electromagnetism)) of free space [N A-2], $r\_{ss}$ is the subsolar standoff distance of the magnetopause [m], and $\mathbf{m}$ is the magnetic dipole moment [A m2] of the source object.

Note that the magnetic moment of a dipole magnet can be approximated as:
$$
\lvert \mathbf{m} \rvert \approx \frac{ 2 \ \pi \ r^{3} }{ \mu\_{o} } \lvert \mathbf{B} \rvert \tag{1}
$$
where $\mathbf{B}$ is the magnetic field [T] vector.

Magnetars have $B\_{o}$ ~ 109 – 1011 T and radii of ~20 km, thus their magnetic moments are $\lvert \mathbf{m} \rvert$ ~ 1028 – 1030 A m2. For comparison, Jupiter has the largest [magnetic field](https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter) strength of all planetary bodies in the solar system, with a magnetic moment of ~1027 A m2 [e.g., see [*Durand-Manterola*, 2009](https://doi.org/10.1016/j.pss.2009.06.024)]. Note that the mean equatorial Jovian radius is ~3575 times larger than a magnetar.

Typical solar wind values near Earth are $\rho\_{sw}$ ~ 1.673 x 10-20 kg m-3 and $V\_{sw}$ ~ 4 x 105 m/s [e.g., see [*Wilson et al.*, 2021](https://doi.org/10.1029/2020RG000714)]. The magnitude of $V\_{sw}$ stays constant out past Jupiter but $\rho\_{sw}$ ~ r-2, thus the mass density should be roughly 25 times lower at Jupiter than Earth (which it usually is).

Solving Equation 0 using these values we find that for a magnetar we have $r\_{ss}$ ~ 3–15 x 105 $R\_{Mag}$ (where $R\_{Mag}$ is the magnetar radius) and for Jupiter $r\_{ss}$ ~ 52 $R\_{J}$ (where $R\_{J}$ ~ 71492 km is the mean Jovian equatorial radius), which is close to the observed value. For comparison, Earth has $\lvert \mathbf{m} \rvert$ ~ 8 x 1022 A m2, which corresponds to $r\_{ss}$ ~ 12 $R\_{E}$ (where $R\_{E}$ ~ 6378 km is the mean Earth equatorial radius). If we normalize the magnetar magnetopause $r\_{ss}$ by $R\_{J}$, we get a range of ~91–423, i.e., ~2-8 times larger than the Jovian magnetosphere (which is the largest natural, identifiable system within the heliosphere).


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