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I've been mulling over this for a while now. How would you describe a shielding system designed to minimize and/or counteract the damage caused by a collision with an incoming object? The simplest way, to me, would seem to be a conservative force field -- that is, a force field where the total energy (potential plus kinetic) of an object is always the same. Gravitational fields are one such field.

If I remember correctly, Curtis Saxton described energy shielding as a dissipation field, so it would make sense to apply the same basic concepts to particle shielding as well. Since, with a conservative vector field, total energy remains constant, the system could be quantified in terms of a time rate of change of energy, much like energy shields.

In such a field, the requisite velocity required for an object to "penetrate" the shields could be expressed very much like escape velocity is in Earth's gravitational field, only with a different coordinate system and treating x = 0 as maximum potential.

While the system does behave like gravity in some respects, it does not have to be a gravity-based system which would explain why we don't observe a warped spacetime around shielded ships (gravity is the only force which creates such a phenomenon, as far as I know; EM fields do not). For a visual, imagine a star destroyer with a bunch of arrows pointing outward from its center of gravity in all directions. Imagine there is a small sphere sitting inside the ship, and that each of those lines is perpendicular to a point in the surface of that sphere.

Now, can anyone think of any observed instances in canon or official which would basically refute this theory, or ways which it could be improved to encompass more of the observations we have?

I would say a conventional force, like gravity, only with the opposite polarity. But "force fields" are more like surfaces made of really tiny offset field points instead of ones located around the generator. ::

Durandal wrote:I've been mulling over this for a while now. How would you describe a shielding system designed to minimize and/or counteract the damage caused by a collision with an incoming object? The simplest way, to me, would seem to be a conservative force field -- that is, a force field where the total energy (potential plus kinetic) of an object is always the same. Gravitational fields are one such field.

If I remember correctly, Curtis Saxton described energy shielding as a dissipation field, so it would make sense to apply the same basic concepts to particle shielding as well. Since, with a conservative vector field, total energy remains constant, the system could be quantified in terms of a time rate of change of energy, much like energy shields.

In such a field, the requisite velocity required for an object to "penetrate" the shields could be expressed very much like escape velocity is in Earth's gravitational field, only with a different coordinate system and treating x = 0 as maximum potential.

While the system does behave like gravity in some respects, it does not have to be a gravity-based system which would explain why we don't observe a warped spacetime around shielded ships (gravity is the only force which creates such a phenomenon, as far as I know; EM fields do not). For a visual, imagine a star destroyer with a bunch of arrows pointing outward from its center of gravity in all directions. Imagine there is a small sphere sitting inside the ship, and that each of those lines is perpendicular to a point in the surface of that sphere.

Now, can anyone think of any observed instances in canon or official which would basically refute this theory, or ways which it could be improved to encompass more of the observations we have?

Shouldn't such a field deflect the asteroid? Yet, in TESB, we saw the asteroid ... for a lack of a better word explode on the shields.

PainRack wrote:Shouldn't such a field deflect the asteroid? Yet, in TESB, we saw the asteroid ... for a lack of a better word explode on the shields.

It DID deflect it. It's just that the decellerative forces were so great that the thing also blew the fuck up in the process.

kojikun wrote:I would say a conventional force, like gravity, only with the opposite polarity. But "force fields" are more like surfaces made of really tiny offset field points instead of ones located around the generator. ::

You're falling victim to the common Star Trek definition of a force field, which is in fact, utterly inaccurate. Gravitational fields are force fields are force fields, but they don't have discrete boundaries. Ditto for EM fields. Force fields, generally speaking, are 3-dimensional vector fields. Of the four forces, there's not one that's purely 2-dimensional, meaning that it only affects bodies at a certain radius. The nuclear strong force has a boundary, but that is not the same thing.

Gravity has no polarity, by the way. If you mean a repulsive force rather than an attractive force, yes that's what I was getting at. Again, you're using the warped Star Trek definition of "polarity."

PainRack: Yes, you're right. Objects would simply be repulsed, rather than destroyed. The force field could be manipulated in such a way as to sheer the object and destroy it though. That starts bordering on circular reasoning though.

1. It was stated that a particle shield would make the exhaust port unable to function. Your theoretical shield would only serve that function better while providing defense against incoming objects.
2. Several (small) asteroids bounced from the Falcon. Since you said that such a shield would be 3D, it means that those actually penetrated that shield and and bounced from the hull (since that shield cannot change the vector of an incoming object from one moment to an other).

But maybe I am simply wrong.

vakundok wrote:1. It was stated that a particle shield would make the exhaust port unable to function. Your theoretical shield would only serve that function better while providing defense against incoming objects.

That seems unlikely, since it was a thermal exhaust port. Thermal excesses by definition are heat, which would fall into the domain of energy shielding. Shielding the exhaust port against energy weapons would defeat its purpose.

2. Several (small) asteroids bounced from the Falcon. Since you said that such a shield would be 3D, it means that those actually penetrated that shield and and bounced from the hull (since that shield cannot change the vector of an incoming object from one moment to an other).

But maybe I am simply wrong.

A vector field can change objects' vectors; that's what they do. By simply slowing an object down or speeding it up, you change its vector. Also, a gravitational field will change the direction of an object's velocity vector by pulling it downward. If you find the component x and y vectors of an object traveling under the influence of Earth's gravitational field at different points, they will be of different magnitudes at each point if there are no other forces acting on the object. Hence, the object's velocity vector is undergoing a change in magnitude and direction.

It's possible that, if the shields I describe are in fact accurate, that the asteroids didn't really hit the hull of the Falcon. They could have been deflected by the vector field very close to the hull (meaning that they had enough momentum initially to penetrate) and could have strained the shield generators. After all, that force has to go somewhere.

Durandal wrote:

vakundok wrote:1. It was stated that a particle shield would make the exhaust port unable to function. Your theoretical shield would only serve that function better while providing defense against incoming objects.

That seems unlikely, since it was a thermal exhaust port. Thermal excesses by definition are heat, which would fall into the domain of energy shielding. Shielding the exhaust port against energy weapons would defeat its purpose.

Unlikely? Until someone quotes the novelisation of ANH (it was stated in it):

ANH published screenplay wrote:DODONNA
Only a precise hit will set up a
chain reaction. The shaft is ray-
shielded, so you'll have to use
proton torpedoes.

Durandal wrote:

vakundok wrote:2. Several (small) asteroids bounced from the Falcon. Since you said that such a shield would be 3D, it means that those actually penetrated that shield and and bounced from the hull (since that shield cannot change the vector of an incoming object from one moment to an other).

But maybe I am simply wrong.

A vector field can change objects' vectors; that's what they do. By simply slowing an object down or speeding it up, you change its vector. Also, a gravitational field will change the direction of an object's velocity vector by pulling it downward. If you find the component x and y vectors of an object traveling under the influence of Earth's gravitational field at different points, they will be of different magnitudes at each point if there are no other forces acting on the object. Hence, the object's velocity vector is undergoing a change in magnitude and direction.

It's possible that, if the shields I describe are in fact accurate, that the asteroids didn't really hit the hull of the Falcon. They could have been deflected by the vector field very close to the hull (meaning that they had enough momentum initially to penetrate) and could have strained the shield generators. After all, that force has to go somewhere.

I ment radical (90 or even more degrees in direction or speed cut to zero) change from one moment to an other.
1: Your theoretical shield cannot produce the "bang" sound we heard without actually being penetrated, since it is otherwise able to nullify the momentum (at least the part of it which points toward the defended object) of the incoming object.
2: I can remember no sign of any incoming objects slowing down. All I can remember suggests 2D particle shielding (shield with boundaries).
2B: We saw that the rebel fleet has no warning about the shield of the DS2, despite the shields were active. Your theoretical shield would require that they were unable to notice that they suffered some negative acceleration from the shield.

vakundok wrote:Until someone quotes the novelisation of ANH (it was stated in it):

ANH published screenplay wrote:DODONNA
Only a precise hit will set up a
chain reaction. The shaft is ray-
shielded, so you'll have to use
proton torpedoes.

That contradicts the established purposes of ray and particle shielding. Putting an energy shield around the port would prevent heat from escaping.

I ment radical (90 or even more degrees in direction or speed cut to zero) change from one moment to an other.

1: Your theoretical shield cannot produce the "bang" sound we heard without actually being penetrated, since it is otherwise able to nullify the momentum (at least the part of it which points toward the defended object) of the incoming object.

This is why I mentioned strain on the shield generators.

2: I can remember no sign of any incoming objects slowing down. All I can remember suggests 2D particle shielding (shield with boundaries).

Yes, I remember a quote from one of the novels that talks about passing through particle shields. However, in order to counteract the momentum of an incoming object, you must have some sort of force field in place, which means a vector field. It doesn't have to be exactly as I've said, but force vectors must be present.

2B: We saw that the rebel fleet has no warning about the shield of the DS2, despite the shields were active. Your theoretical shield would require that they were unable to notice that they suffered some negative acceleration from the shield.

That depends on how the magnitudes of the force vectors drop off as a function of radius. Gravity drops off with the square of the radius. It would make sense for whoever designed these to drop off strength as a function of a greater exponent to prevent particle shields from interfering with friendly ships' maneuvering capabilities.

Unless it vented, say, hot gasses instead of just radiation.

I beleive it vents out neutrinos, something about the superfluid they use as a coolant makes for the energy beign converted into them and released IIRC

Durandal wrote:That contradicts the established purposes of ray and particle shielding. Putting an energy shield around the port would prevent heat from escaping.

That would depend on the method of heat dissipation, now, wouldn't it? Canonicaly, the shaft is ray-shielded but not particle shielded, and reasons for such were stated. Therefore, photon radiation must not be the method used. It seems likely high-energy massive particles are released instead, for whatever reason. (Perhaps the designers figured a beam weapon would have a greater chance of doing critical damage, and thus opted to shield against that instead and set up the exhaust system to work with that configuration. Or some other reason; it doesn't really matter.)

Ender wrote:I beleive it vents out neutrinos, something about the superfluid they use as a coolant makes for the energy beign converted into them and released IIRC

I seriously doubt that particles with a mean free path of roughly 6,000 light years would need a special vent dedicated to their exhaust.

Howedar wrote:Unless it vented, say, hot gasses instead of just radiation.

Point taken.

Durandal:
Fact:
The function of the exhaust port made it impossible to use particle shields.

Consequence:
Particle shields are 'double blind', so no way in, no way out. (This is also supported by lower level sources, like WEG.)
Your theoretical shield is not. So, your theoretical shield may will be used in reality, but it is not the SW particle shield.
I think no further discussion is needed on that, unless you unnecesserely question the highest levels of canon.

Side note:
If you use an even higher factor, you will soon arrive to a 2D shield very close to the hull with some leakage. Still, it will be one directional.

Durandal wrote:That seems unlikely, since it was a thermal exhaust port. Thermal excesses by definition are heat, which would fall into the domain of energy shielding. Shielding the exhaust port against energy weapons would defeat its purpose.

It might have released the thermal waste as a particle stream or something instead of radiation.

EDIT:
Eh, I see I'm late with this theory.

Though it makes me wonder, wouldn't the energy shields strip the energy being released as EM radiation(glow) from the released particles?
Maybe that captured energy is just released as a burst of neutrinos instead, it'd also explain why we don't really see the waste, much of the energy of the hypothetical particle exhaust released as radiation has been stripped so they are dark.

There's also the possibility of shields having thresholds, ambient light isn't stopped by energy shields as we can see many times in the movies.

vakundok wrote:Consequence:
Particle shields are 'double blind', so no way in, no way out. (This is also supported by lower level sources, like WEG.)
Your theoretical shield is not. So, your theoretical shield may will be used in reality, but it is not the SW particle shield.
I think no further discussion is needed on that, unless you unnecesserely question the highest levels of canon.

Except that TPM showed that while they are double blind, they are also velocity dependent. If the shields in that area were set to allow the exhaust through, but halt others, this could work

Ender wrote:

vakundok wrote:Consequence:
Particle shields are 'double blind', so no way in, no way out. (This is also supported by lower level sources, like WEG.)
Your theoretical shield is not. So, your theoretical shield may will be used in reality, but it is not the SW particle shield.
I think no further discussion is needed on that, unless you unnecesserely question the highest levels of canon.

Except that TPM showed that while they are double blind, they are also velocity dependent. If the shields in that area were set to allow the exhaust through, but halt others, this could work

True. Except that not 'were set' but 'could be set' for me, since I do not know much about the configuration limits of the shields.
I think you otherwise agree that Durandal's theory cannot be the same one used in SW.
Side note:
(or Why am I nitpicking?)
The hungarian version of the novelisation of ANH states that a particle shield would not allow the system to function at all. The novelisation of TPM (hungarian version again) describes the gungan shield as being designed to deflect large, slow moving objects (such as the tanks) and to ward off fast objects which generate extreme heat (such as blasts). So, in my resources there is a suggestion that it would be possible against a statement that it wasn't.

Off topic:
Could someone show me any other (than the 'The shaft is ray-
shielded') sign of separate ray and particle shields from the OT and the prequels?

vakundok wrote:Durandal:
Fact:
The function of the exhaust port made it impossible to use particle shields.

I have to dig out my ANH novel, but IIRC, it is possible to view Dodonna statement as"They built an exhaust port, its function prevents a particle shield from being installed.", as opposed to the shield preventing the exhaust port from functioning.

its semantics of course, but I find it absurd that hot, energised ions can't leave the shield, when weapons fire like turbolasers and ion cannons presumably can.



However, I still don't think its a just a simple "Force Vector". How could such a shield, discriminate against objects like asteroids, but allow fighter craft through? Of course, we can also assume that shields have to be lowered during the launching of fighter craft, but if so,what keeps the air in the docking bay during Vader visit in ROTJ? Also, the destruction of the asteroid in TESB. Why should there be a shearing effect? Won't it introduce a whole new realm of complexity to the shields?

The simple duality shields in WEG IMO needs to be replaced by the SWU having a variety of shield types, of which they have certain "energy shield" and "particle shield" properties.

PainRack wrote:However, I still don't think its a just a simple "Force Vector". How could such a shield, discriminate against objects like asteroids, but allow fighter craft through? Of course, we can also assume that shields have to be lowered during the launching of fighter craft, but if so,what keeps the air in the docking bay during Vader visit in ROTJ? Also, the destruction of the asteroid in TESB. Why should there be a shearing effect? Won't it introduce a whole new realm of complexity to the shields?

The simple duality shields in WEG IMO needs to be replaced by the SWU having a variety of shield types, of which they have certain "energy shield" and "particle shield" properties.

My shielding system makes perfect sense for launching fighters, and frankly, it's one of the only models I've seen that can explain the launch of fighters while the shields are still raised. Since the shield vectors point outward, all the fighter has to do is let itself travel along one of those vectors, and it can launch without using any of its own power at all.

The asteroid destruction in TESB could be accomplished through manipulation of the field vectors to increase the pressure applied to the incoming object.

I should also note that I did not consider Gungan shielding technology when forming this model. I saw no reason to. It looked and acted nothing like what we saw in the OT. When raised, it meanders up, it is visible to the naked eye, seems to act more like a viscous fluid than a force field and blocked blaster bolts. Gungan technology seems very far removed from the rest of galactic civilization.

As for the double-blind aspect of the exhaust port, it makes perfect sense. The shields I propose are omni-directional and elliptical. Put a particle shield like the one I'm describing on that exhaust port, and the particles will be suppressed.

Could you post some WEG quotes showing that particle shields are generally double-blind?

In the Courtship of Princess Leia, the Falcon's particle shields must be lowered before the torpedoes pass through.

Thrawn remembers to drop the docking bay shields before launching fighters (and remembers to cover that big gaping hole up while doing so too) in HTTE.

Just to thow out a quick idea about why the thermal exhaust port was ray shielded: perhaps to create a certain amount of heat energy "backpressure" for the main reactor ala Le Chatlier?

The port did lead directly into the reactor unlike the main exhaust port and as someone pointed out above, the function of the port nessesitated an energy shield. The intensity of the field could be controlled depending on needs.

There is an other example in TESB novelisation (and in the fourth draft of the shooting script), the shield of the probe droid. When the night came the probe droid created a force field dome which was quickly covered by snow. I think the snow could not cover the shield what Durandal proposed.
However it is possible that it was not a regular particle shield. Especially because it became a 'solid shape' and I do not know what exactly it means.

vakundok wrote:There is an other example in TESB novelisation (and in the fourth draft of the shooting script), the shield of the probe droid. When the night came the probe droid created a force field dome which was quickly covered by snow. I think the snow could not cover the shield what Durandal proposed.

The perceived border of the shield is relative to the acceleration of the incoming object. For a second, just assume that this shielding system acts like gravity, meaning that its induced acceleration decreases inversely proportionally to the square of the radius from the center. If Hoth has a gravitational acceleration of 10 m/s², then the snow flakes will actually hover in equilibrium at approximately the radius where the shield's induced acceleration is -10 m/s², because the shield will be exerting the equivalent of a drag force on them. Of course, this precludes the interference of wind, but that would apply to any kind of shield anyway.