Particle Beam Weapons - Revision history

Lwcamp: /* Separation of neutral beams */

2026-11-01T21:27:24Z

Separation of neutral beams

← Older revision		Revision as of 13:27, 1 November 2026
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	will promptly ionize the atom, ripping away its electron. Here, <i>e</i> = 1.60×10<sup>-19</sup> C is the magnitude of the electric charge of the electron. For fields close to but a bit weaker than this, the electron can still rapidly pop off due to quantum tunneling<ref>Ph. Durand and I. Paidarová, “Ionization of the hydrogen atom: from weak to strong static electric fields,” The European Physical Journal D, Vol. 26, pg. 253-259, 2003.</ref>. In general, expect that for fields greater in magnitude than (very approximately) <i>E<sub>b</sub></i> / (10 <i>e</i> <i>a</i>) the electron will be quickly removed, while for fields weaker than this the electrons will stay on their atoms.		will promptly ionize the atom, ripping away its electron. Here, <i>e</i> = 1.60×10<sup>-19</sup> C is the magnitude of the electric charge of the electron. For fields close to but a bit weaker than this, the electron can still rapidly pop off due to quantum tunneling<ref>Ph. Durand and I. Paidarová, “Ionization of the hydrogen atom: from weak to strong static electric fields,” The European Physical Journal D, Vol. 26, pg. 253-259, 2003.</ref>. In general, expect that for fields greater in magnitude than (very approximately) <i>E<sub>b</sub></i> / (10 <i>e</i> <i>a</i>) the electron will be quickly removed, while for fields weaker than this the electrons will stay on their atoms.

	It is useful to note that <i>E<sub>b</sub></i>/<i>e</i> is just the binding energy in units of eV. The most weakly bound electrons are usually bound to their atom with about 10 eV of energy. Atoms are typically about 10<sup>-10</sup> m in radius. Thus, you can expect fields of around 10<sup>10</sup> to 10<sup>11</sup> V/m to directly ionize atoms. If we call this threshold value 𝓔<sub>T</sub>, then a beam will be ionized when passing through a field with strength greater than		It is useful to note that <i>E<sub>b</sub></i>/<i>e</i> is just the binding energy in units of eV. The most weakly bound electrons are usually bound to their atom with about 10 eV of energy. Atoms are typically about 10<sup>-10</sup> m in radius. Thus, you can expect fields of around 10<sup>10</sup> to 10<sup>11</sup> V/m to directly ionize atoms. If we call this threshold value 𝓔<sub>T</sub>, and using the Lorentz transform of a magnetic field to an electric field in the rest frame of the atom, then a beam will be ionized when passing through a magnetic field with strength greater than
	<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">		<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
	<i>B</i> sin(θ) > 𝓔<sub>T</sub> / (γ <i>v</i>)		<i>B</i> sin(θ) > 𝓔<sub>T</sub> / (γ <i>v</i>)

Lwcamp: /* Separation of neutral beams */

2026-10-29T19:53:20Z

Separation of neutral beams

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 </table>
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-For a partially eroding beam, the polarized region that was peeled off by the field still acts to screen the remaining neutral portion, at least to within this approximation, leaving the still-neutral beam to hit the target.
+For a partially eroding beam, the polarized region that was peeled off by the field still acts to screen the remaining neutral portion, at least to within this approximation, leaving the still-neutral beam to hit the target.  The fraction of the beam that is charged and stripped away by the field is
 <div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
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Lwcamp: /* Plasma magnets */

2026-10-28T00:53:06Z

Plasma magnets

← Older revision		Revision as of 16:53, 27 October 2026
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	The deflection for a shot aimed right at the spacecraft at the position of the spacecraft can be estimated by setting <i>x</i> = 0 and only taking the first half of the integral (so ignore the factor of 2)		The deflection for a shot aimed right at the spacecraft at the position of the spacecraft can be estimated by setting <i>x</i> = 0 and only taking the first half of the integral (so ignore the factor of 2)
	<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">		<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
	<i>q</i> <i>B</i>(<i>0</i>) <i>R</i><sub>0</sub> ~~ln[~~<i>R</i><sub>m</sub>/<i>R</i><sub>0</sub>] / (<i>p</i> <i>R</i><~~sub~~>m</~~sub~~>)		<i>q</i> <i>B</i>(<i>0</i>) <i>R</i><sub>0</sub> <i>R</i><sub>m</sub> ln[<i>R</i><sub>m</sub>/<i>R</i><sub>0</sub>] / <i>p</i>
	</div>		</div>
	This is an additional overestimate because it fails to account for how the deflection builds up over distance during the integration, but it should still give something of an order-of-magnitude and upper limit estimate of what kind of deflections might be expected.		This is an additional overestimate because it fails to account for how the deflection builds up over distance during the integration, but it should still give something of an order-of-magnitude and upper limit estimate of what kind of deflections might be expected.

Lwcamp: /* Hitting Your Target */

2026-10-27T23:57:00Z

Hitting Your Target

← Older revision		Revision as of 15:57, 27 October 2026
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	It doesn't do much to have the most horrifically powerful death ray if it can't hit. What are the challenges for directing your beam of radioactive fury onto your enemies?		It doesn't do much to have the most horrifically powerful death ray if it can't hit. What are the challenges for directing your beam of radioactive fury onto your enemies?

	We have already mentioned the challenges of stray magnetic ~~fields~~ that are part of the ambient environment messing with your targeting. This will be a challenge when you are launching beams of charged particles. And we've discussed some of the means of getting around this, like using neutralized beams.		We have already mentioned the [[Particle_Beam_Weapons#Magnetic_fields\|challenges of stray magnetic field]] that are part of the ambient environment messing with your targeting. This will be a challenge when you are launching beams of charged particles. And we've discussed some of the means of getting around this, like using neutralized beams.

	But another issue that will be a challenge at very long ranges is dealing with [[Jitter\|jitter]]. A weapon made out of a linac will be very long, and so it will be rather wibbly. This could make its jitter problems worse. A synchrotron might not be so badly affected; and for any future hypothetical high energy wakefield accelerators, no one really knows what they'll be like. There are certainly tricks you can play to reduce jitter (see the previously linked jitter page), but at ranges approaching a light second it's certainly plausible that it will be difficult to land a hit.		But another issue that will be a challenge at very long ranges is dealing with [[Jitter\|jitter]]. A weapon made out of a linac will be very long, and so it will be rather wibbly. This could make its jitter problems worse. A synchrotron might not be so badly affected; and for any future hypothetical high energy wakefield accelerators, no one really knows what they'll be like. There are certainly tricks you can play to reduce jitter (see the previously linked jitter page), but at ranges approaching a light second it's certainly plausible that it will be difficult to land a hit.

Lwcamp: /* Damage */

2026-10-27T23:55:48Z

Damage

← Older revision		Revision as of 15:55, 27 October 2026
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	In addition to the radiation and thermal effects, a particle beam can also produce a sharp electromagnetic pulse that can damage semiconductor electronics.		In addition to the radiation and thermal effects, a particle beam can also produce a sharp electromagnetic pulse that can damage semiconductor electronics.

			== Hitting Your Target ==

			It doesn't do much to have the most horrifically powerful death ray if it can't hit. What are the challenges for directing your beam of radioactive fury onto your enemies?

			We have already mentioned the challenges of stray magnetic fields that are part of the ambient environment messing with your targeting. This will be a challenge when you are launching beams of charged particles. And we've discussed some of the means of getting around this, like using neutralized beams.

			But another issue that will be a challenge at very long ranges is dealing with [[Jitter\|jitter]]. A weapon made out of a linac will be very long, and so it will be rather wibbly. This could make its jitter problems worse. A synchrotron might not be so badly affected; and for any future hypothetical high energy wakefield accelerators, no one really knows what they'll be like. There are certainly tricks you can play to reduce jitter (see the previously linked jitter page), but at ranges approaching a light second it's certainly plausible that it will be difficult to land a hit.

	== Design It Yourself ==		== Design It Yourself ==

Lwcamp: /* Plasma magnets */

2026-10-27T04:58:18Z

Plasma magnets

← Older revision		Revision as of 20:58, 26 October 2026
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	==== Plasma magnets ====		==== Plasma magnets ====

	Usually, to make a really big magnetic field you would run current through a really big conductive loop. But really big things are heavy and expensive. One way around this could be to use the ambient space plasma to carry the electric current rather than any kind of wire. In order to make this current, you use the same mechanism used in a rotary induction electric motor: you generate a rotating magnetic field and induce a current in the conductive loop (in this case, the space plasma). How do you make a rotating magnetic field? The method proposed<ref name="Slough2006">John Slough, "The Plasma Magnet", NASA Institute for Advanced Concepts Phase II Final Report (2006) https://www.niac.usra.edu/files/studies/final_report/917Slough.pdf</ref> is to use an antenna of four much smaller current loops as electromagnets at 90&~~degree~~; to each other, and sinusoidally vary the current through the loops with a respective 90&~~degree~~; phase difference between them. When this is done, a circular current is induced in the space plasma and the self-force of a magnetic field on its generating current inflates the current loop to much larger radii. You end up with a current sheet in the plane of the rotating field's rotation circulating about the antenna nearly synchronously with the field rotation. This current then creates a normal dipolar magnetic field as with any current loop. The current sheet and the resulting magnetic field expand until the magnetic field's pressure equals that of the ambient space plasma. This gives an enormous region of magnetic field from a relatively small and lightweight system.		Usually, to make a really big magnetic field you would run current through a really big conductive loop. But really big things are heavy and expensive. One way around this could be to use the ambient space plasma to carry the electric current rather than any kind of wire. In order to make this current, you use the same mechanism used in a rotary induction electric motor: you generate a rotating magnetic field and induce a current in the conductive loop (in this case, the space plasma). How do you make a rotating magnetic field? The method proposed<ref name="Slough2006">John Slough, "The Plasma Magnet", NASA Institute for Advanced Concepts Phase II Final Report (2006) https://www.niac.usra.edu/files/studies/final_report/917Slough.pdf</ref> is to use an antenna of four much smaller current loops as electromagnets at 90° to each other, and sinusoidally vary the current through the loops with a respective 90° phase difference between them. When this is done, a circular current is induced in the space plasma and the self-force of a magnetic field on its generating current inflates the current loop to much larger radii. You end up with a current sheet in the plane of the rotating field's rotation circulating about the antenna nearly synchronously with the field rotation. This current then creates a normal dipolar magnetic field as with any current loop. The current sheet and the resulting magnetic field expand until the magnetic field's pressure equals that of the ambient space plasma. This gives an enormous region of magnetic field from a relatively small and lightweight system.

	The system proposed in the initial study would use an antenna approximately 10 meters in radius and produce a region of field approximately 30 km in radius at Earth's orbit. The field inside would not be constant - at the edges it would be 50 nT, giving the right pressure to keep out the solar wind at Earth's orbit. A circulating current sheet produces a field that falls off as 1/<i>r</i> with distance, meaning that adjacent to the antenna the field would be about 0.15 mT. Using the methods in the box below, we can estimate that this particular design as part of a spacecraft's shields will not deflect a TeV electron beam by more than a few centimeters, which is usually insufficient to force a miss. However, it could potentially be useful for a drone magnet, where the much larger distance between the magnetic field and the target spacecraft would allow a small deflection angle to give perhaps tens or low hundreds of meters change in beam location near the target at near light second ranges. The relatively low field and gradual bend of the incident beam suggests that synchrotron radiation will not be an issue; however this does not exclude more powerful plasma magnet designs causing significant synchrotron radiation effects.		The system proposed in the initial study would use an antenna approximately 10 meters in radius and produce a region of field approximately 30 km in radius at Earth's orbit. The field inside would not be constant - at the edges it would be 50 nT, giving the right pressure to keep out the solar wind at Earth's orbit. A circulating current sheet produces a field that falls off as 1/<i>r</i> with distance, meaning that adjacent to the antenna the field would be about 0.15 mT. Using the methods in the box below, we can estimate that this particular design as part of a spacecraft's shields will not deflect a TeV electron beam by more than a few centimeters, which is usually insufficient to force a miss. However, it could potentially be useful for a drone magnet, where the much larger distance between the magnetic field and the target spacecraft would allow a small deflection angle to give perhaps tens or low hundreds of meters change in beam location near the target at near light second ranges. The relatively low field and gradual bend of the incident beam suggests that synchrotron radiation will not be an issue; however this does not exclude more powerful plasma magnet designs causing significant synchrotron radiation effects.

Lwcamp: /* Separation of neutral beams */

2026-10-27T04:53:42Z

Separation of neutral beams

← Older revision		Revision as of 20:53, 26 October 2026
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	</table>		</table>

	Example: Let's consider a 1 GeV neutralized proton beam from a synchrotron, with a beam current of 200 kA in each bunch (incidentally, if a bunch is 5 cm long this means that each bunch packs 38 kJ worth of energy). The speed of the bunch is 87% the speed of light, or 262 million m/s, with a γ of 2.07. Consider when the beam's focus takes it to a radius of 5 cm (or 0.05 m, for our calculation). Plugging this in, we find that the protons in the bunch will separate from the electrons in a field with a transverse component greater than about 2.1 T, and the bunch will pass through the field with only ~~gradual~~ losses if the transverse component is much smaller than this.		Example: Let's consider a 1 GeV neutralized proton beam from a synchrotron, with a beam current of 200 kA in each bunch (incidentally, if a bunch is 5 cm long this means that each bunch packs 38 kJ worth of energy). The speed of the bunch is 87% the speed of light, or 262 million m/s, with a γ of 2.07. Consider when the beam's focus takes it to a radius of 5 cm (or 0.05 m, for our calculation). Plugging this in, we find that the protons in the bunch will separate from the electrons in a field with a transverse component greater than about 2.1 T, and the bunch will pass through the field with only minimal losses if the transverse component is much smaller than this.

	Example: We'll take the same 1 GeV beam, but this time recombine the electrons with protons to make hydrogen atoms. An electron is bound to a hydrogen atom with an energy of 13.6 eV (the Ryberg constant) and the radius of the electron orbital in a hydrogen atom is 0.529×10<sup>-10</sup> m (the Bohr radius). This gives a threshold electric field for prompt ionization of hydrogen of 2.57×10<sup>11</sup> V/m. We will get this with a transverse component of the magnetic field of 474 T. Above this field the atoms promptly ionize and electrons are stripped away from the protons. For fields higher than roughly 1/10 of this – so about 40 to 50 T – you may still get significant ionization by quantum tunneling; lower than this your losses from the beam due to field-induced ionization are likely negligible.		Example: We'll take the same 1 GeV beam, but this time recombine the electrons with protons to make hydrogen atoms. An electron is bound to a hydrogen atom with an energy of 13.6 eV (the Ryberg constant) and the radius of the electron orbital in a hydrogen atom is 0.529×10<sup>-10</sup> m (the Bohr radius). This gives a threshold electric field for prompt ionization of hydrogen of 2.57×10<sup>11</sup> V/m. We will get this with a transverse component of the magnetic field of 474 T. Above this field the atoms promptly ionize and electrons are stripped away from the protons. For fields higher than roughly 1/10 of this – so about 40 to 50 T – you may still get significant ionization by quantum tunneling; lower than this your losses from the beam due to field-induced ionization are likely negligible.

Lwcamp: /* Separation of neutral beams */

2026-10-27T04:48:50Z

Separation of neutral beams

← Older revision		Revision as of 20:48, 26 October 2026
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	<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">		<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
	<table>		<table>
	<tr><td> <i>B</i> sin(θ) &Lt; <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td>       <td> Beam is partially eroded.		<tr><td> <i>B</i> sin(θ) < <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td>       <td> Beam is partially eroded.
	<tr><td> <i>B</i> sin(θ) > <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td> <td> Beam promptly separates.		<tr><td> <i>B</i> sin(θ) ≥ <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td> <td> Beam promptly separates.
	</table>		</table>
	</div>		</div>

Lwcamp: /* Magnetic fields */

2026-10-27T02:13:51Z

Magnetic fields

← Older revision		Revision as of 18:13, 26 October 2026
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	As an example, the Earth has a magnetic field strength of about 5×10<sup>-5</sup> tesla near its surface, and falling off farther away. If you are shooting a 1 TeV electron beam past the Earth, your beam is likely to bend by several milliradians (with the exact deflection depending on how close you are skimming the Earth). If you are in a medium Earth orbit and shooting at another target also in a medium Earth orbit on a trajectory that goes near the Earth, then without correcting for the magnetic field your beam will likely be off-target by tens to hundreds of kilometers.		As an example, the Earth has a magnetic field strength of about 5×10<sup>-5</sup> tesla near its surface, and falling off farther away. If you are shooting a 1 TeV electron beam past the Earth, your beam is likely to bend by several milliradians (with the exact deflection depending on how close you are skimming the Earth). If you are in a medium Earth orbit and shooting at another target also in a medium Earth orbit on a trajectory that goes near the Earth, then without correcting for the magnetic field your beam will likely be off-target by tens to hundreds of kilometers.

	For another example, the interplanetary magnetic field is about 10<sup>-9</sup> tesla. If you shoot that same 1 TeV electron beam at a target 0.1 light seconds away, you are likely to be off by a couple hundred meters.		For another example, the interplanetary magnetic field is about 10<sup>-9</sup> tesla at Earth's distance from the sun. If you shoot that same 1 TeV electron beam at a target 0.1 light seconds away, you are likely to be off by a couple hundred meters.

	<table border=1>		<table border=1>

Lwcamp: /* Separation of neutral beams */

2026-10-27T02:06:28Z

Separation of neutral beams

← Older revision		Revision as of 18:06, 26 October 2026
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	<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">		<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
	<table>		<table>
	<tr><td> <i>B</i> sin(θ) &Lt; <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td>       <td> Beam ~~gradually erodes~~.		<tr><td> <i>B</i> sin(θ) &Lt; <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td>       <td> Beam is partially eroded.
	<tr><td> <i>B</i> sin(θ) > <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td> <td> Beam promptly separates.		<tr><td> <i>B</i> sin(θ) > <i>I</i> / (π ε<sub>0</sub> <i>v</i><sup>2</sup> <i>R</i>) <td> <td> Beam promptly separates.
	</table>		</table>
	</div>		</div>
	For a ~~gradually~~ eroding beam, ~~you can figure~~ that if the ~~magnetic deflection of~~ the ~~positive component is not much larger than the beam radius~~, ~~most of~~ the beam ~~will still~~ hit ~~its~~ target.		For a partially eroding beam, the polarized region that was peeled off by the field still acts to screen the remaining neutral portion, at least to within this approximation, leaving the still-neutral beam to hit the target.
	<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">		<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
	<table><tr><td>		<table><tr><td>