What is the most important way to generate charged particles during gas discharge and why

Collision ionization is the most important way to generate charged particles during gas discharge. This is because the electrons are small in size and their free travel (the distance traveled by the interstitial point between two collisions) is much greater than that of the ions, so the kinetic energy obtained in the electric field is much greater than that of the ions.

The gas sandwiched between the two electrodes, under the action of rising voltage, the corona layer in the gas will continue to expand, and the electron collapse will continue to elongate and develop, forming a flow injection. The flow is constantly extinguished and re-bursted, which is the pulse phenomenon of discharge, which is called brush discharge, one after another, dense at the end of the electrode. If the distance between the electrodes is relatively long (long gap) or the power supply is insufficient, the elongation of the flow will stop and go out after a certain distance.

Sometimes the flow is generated, sometimes it goes out, so the discharge appears in the form of a dendritic spark, which is called a pilot discharge before it reaches the other electrode.

What is the most important way to generate charged particles during gas discharge and why

A discharge phenomenon that occurs when an electric current is passed through a gas. It is usually accompanied by luminescence and vocalization. Depending on the shape and distance of the air pressure, voltage, and current electrodes, the emitting and emitting sound varies depending on the shape and distance of the electrode. Neon, for example.

The main forms of gas discharge are as follows:

Discharge form: different forms of discharge due to different air pressure, current power, and electric field distribution.

1. Glow discharge: fill the entire electrode space, the current density is small, 1ma cm2 5ma cm2, and the whole gap is still in a rising volt-ampere state.

2. Electrical staring and faint discharge: a thin layer of luminescence appears near the high-field strength electrode, and the gap is still in an insulated state.

3. Brush discharge: the bright surface of the thin intermittent discharge channel stretched out by the corona electrode, the current increases, and it is still not broken.

4. Spark discharge: a bright and thin intermittent discharge channel that runs through the two electrodes, and the gap is intermittently broken down by spark discharge.

5. Arc discharge: The conductance of the bright surface is very large, and the gap between the fine discharge channels that continue to penetrate the two electrodes is completely broken down, and the short circuit is continuous.

Manner of gas discharge:

If all ionization factors are removed, the ionized gas will gradually return to neutral gas, which is called deionization. There are three ways to deionize: the electrons first combine with the neutral atom to form a negative ion, and then the negative ion collides with the positive ion and recombines to become two neutral atoms.

Electrons and positive ions diffuse to the wall of the apparatus and attach to it, respectively, and become neutral atoms after recombination. The electrons and the positive ions are recombined.

Under the action of the electric field, when the charged particles move in the gas, on the one hand, they move in the direction of the power line and continuously obtain energy. On the one hand, it collides with gas molecules, makes irregular thermal motion, and constantly loses energy. After several accelerated collisions, they reach a state of constant velocity motion, at which point their average velocity u is proportional to the electric field strength e u=ke.

(1) Corona discharge: For example, light blue-purple glow on the high-voltage line at night, accompanied by a "zizi" sound.

2) Arc discharge: The narrow and bright discharge channel between the electrodes has a popping sound, and the discharge process can be continued. Such as electric welding machines.

Careful observation shows that in the test, the second arc in the center of the electrode has burned before the first arc drifts up and the elongation goes out, so it is continuous and uninterrupted as a whole.

3) Spark discharge: The narrow and bright discharge channel between the electrodes has a popping sound, which cannot be continued during the discharge process. Such as lightning, static sparks between clothes, etc.

4) Glow discharge: the overall luminous discharge phenomenon of gas in confined space, rarefied air, and high voltage. Like neon.

5) Discharge along the surface: the discharge formed by the breakdown of air along the surface of the insulator and bushing.

The gas discharge that occurs along the surface of a solid medium is called an along the surface discharge.

The phenomenon of electrical discharge at the interface between solid (or liquid) and gas (or liquid) in an electric field. The breakdown of the discharge along the surface that develops into penetration between the electrodes is called flashover. The discharge of the side insulator is one of the most common surface discharges in gases.

In practical power equipment, due to the uneven voltage distribution at the interface of the medium.

The flashover voltage along the surface is lower than the breakdown voltage when the medium alone and in the presence of potatoes. The flashover voltage is also affected by factors such as the type of medium, the electric field distribution of the insulation structure, and the surface state (e.g., dirt, moisture).

Therefore, when manufacturing and installing high-voltage power equipment, it is necessary to take measures (change the shape of the electrode, increase the noise radius of the electrode curved transport shed, improve the capacitance distribution between the electrodes, etc.) to improve the electric field distribution in the insulation, so as to reduce the excessive electric field strength in some areas of the equipment insulation structure, and pay attention to prevent pollution flashover (see Discharge on Dirty Surface).

There are several forms of gas discharge:

Glow discharge: Low-pressure gases generally produce glow discharges after ignition. Abnormal discharge:

In glow discharge, if the entire cathode is covered with glow, and then increase the current drawn by the bucket, an abnormal glow discharge occurs. Arc discharge: If the current-limiting resistance of glow discharge is reduced, the discharge current will increase and turn into arc discharge.

Corona discharge: If one or two electrodes are very sharp (i.e., the radius of curvature is small) and a strong local electric field is formed, it can lead to strong excitation and ionization of the gas, and the appearance of a thin layer of light, called the corona layer; The area outside the corona layer, where the electric field is not enough to excite and ionize, is dark, and is called the corona outer zone. This discharge is called corona discharge.

Tangerine Hidden Flower Discharge: This is a type of discharge that occurs when the power supply voltage is high enough to break down the gas, but the power supply is not large enough to sustain continuous discharge. High Frequency Vent Wu Kaidian:

When the frequency increases, the discharge does not have time to extinguish, so it takes the form of a stable discharge: the positive radiant column is located in the middle of the two electrodes, and there are Faraday dark regions on both sides of the positive radiant column, and then two negative radiance regions are immediately adjacent to the two electrodes. This is known as high-frequency discharge.

Pulse discharge: The discharge of a gas under the action of an impulse voltage.

Polarization, conductance, dielectric loss.

Breakdown. Dielectric.

Under the action of electric field, there are mainly polarization, conductance, dielectric loss, and breakdown physical phenomena. When the dielectric is in an applied electric field, an electric dipole appears.

An electric dipole is an electric charge that is close to each other but has a distance between two opposite signs and equal in value.

For example, hydrogen atoms.

If the external electric field is zero, the charge distribution is spherically symmetrical, and the average positions of the positive and negative charges coincide, and no electric dipole is formed. If there is an external electric field, the electric field pulls the negative charge downwards and will have a positive charge.

Pushing upwards, the average position of the positive and negative charges no longer coincides, and an electric dipole will be formed. An electric dipole is going to generate an electric field around it.

Dielectric mainly appears polarization, conductance, dielectric loss, breakdown of these four physical phenomena, Guangdong Power Grid last year test.

The internal electric field is zero, and the dielectric potential is the same everywhere! Nothing.

It has a polarizing effect on dielectrics composed of polar molecules.

Polarization, conductivity, dielectric loss, as if there is a breakdown.