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1answer
63 views

Electric field of electron in alternating potential

I am considering the case of an electron placed in an alternating sinusoidal potential, of frequency 13.56 MHz (frequency typically used for RF plasma generation). Suppose I have a simple 1D set up, ...
2
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0answers
51 views

Are / Why are the H II regions positively charged?

One of the questions in our recent astrophysics course homework was to find the general opacity $\kappa$ of H II regions. We know that the H II regions are almost entirely ionized hydrogen and I ...
2
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0answers
35 views

What are the prerequisites for a free electron and an atom/ion to recombine?

I'm mostly interested about recombination not in plasma (e.g., recombination of beta particles with atoms that they pass by), although the rules are probably the same. Say, there's a free electron ...
0
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1answer
34 views

Explain the equation describing total energy of the electrons in HET

I have this equation describing total energy of the electrons in HET (Hall-effect thruster): $$\frac{\partial (\frac{1}{2}mn(v_{ex}+v_{e\vartheta})^2 + \frac{3}{2}nT_e)}{\partial t}+\frac{\partial (\...
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0answers
44 views

What is the electrical resistivity of air during breakdown?

There is a well-documented theory for breakdown voltage vs pressure in the form of Paschen's law. But what is the trend of the electrical resistivity of air as a function of the electric field ...
1
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1answer
38 views

Electron distribution in Low Earth Orbit

I have been searching online for some kind of pdf function that describes the charged electron distribution in Low Earth Orbit in regards to their energies. Any ideas on whether something like that ...
0
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1answer
58 views

Can wind blow away the ionised gases created by plasma/arc lighters

I understand that for plasma lighters to work, they ionise the air between the electrodes. I am wondering what happens to these ionised gases during lighting. Do they remain ionised for a while and ...
2
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1answer
82 views

How to compute Coulomb scattering rate(in early universe)?

I want to compare Coulomb scattering rate with Hubble's expansion rate. To compute Coulomb scattering rate, I know that $$ \Gamma = n_p\sigma v_{rel} $$ Here, $\sigma = \frac{e^{4}}{(4\pi\...
0
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1answer
48 views

Why are atoms ionized at ICP-MS temps?

If the upper temperature of an ICP-MS (Inductively Coupled Plasma - Mass Spectrometry) plasma is 10,000 kelvin, why are any atoms introduced ionized? 1 eV is equivalent to 11,605 kelvin and the first ...
0
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1answer
42 views

Do high power (W) elecron beams traveling through air have the same “blooming effect” as high power laser beams?

So I am talking about an electron beam where the electrons have sufficient velocity and the beam is intense enough (for example, beam power of at least 1 megawatt) to produce enough energy to ionize ...
4
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1answer
50 views

Can colliding electron further ionise positive ion?

Imagine positive helium ion with +1 charge,basically a helium atom with one electron missing. What if electron with kinetic energy greater than second ionisation energy of helium hit that positive ...
1
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1answer
112 views

How much heat is needed for an atom to be ionized? [duplicate]

We all know that heat or high voltage makes atoms into an excited state, stripping off the electrons off of their nucleus. But how much heat do you exactly need to create plasma, or have the majority ...
-2
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3answers
154 views

Does photon electromagnetic field “shake” charged particles and atoms?

Lets theoreticaly imagine completly stationary particle,like electron for example.Can photon,or photons shake it,or oscillate its position? By that I dont necesarily mean the center position must ...
0
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0answers
40 views

Momentum when slow ion collides with fast electron?

Imagine high voltage alternating frequency glow discharge plasma between two plate electrodes with gas atoms inside. There will be free electrons and positive ions.During first half of the sinewave ...
0
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2answers
410 views

Temperature and energy of ions and electrons at Ionization

For Xenon atom, as the ionization energy is 12.13 eV , does it mean that if 12.13 V is applied, the Xenon atom can be ionized. Also, Could you share, how to find the temperature and energy ...
0
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0answers
80 views

How powerful of an electric current would I need to fully ionize plasma under the specific circumstances below?

in a cylinder shaped vacuum chamber 4 inches in height and 5 in diameter at 1/100th atmosphere, with 3 cathodes at the face arranged in a equilateral triangle in exactly between the center and and the ...
1
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0answers
62 views

How ionized is the plasma in a Crookes tube

How ionized is the plasma in a Crookes tube, at $10^{−6}$ to $5 \times 10^{−8}$ atmosphere ($7 \times 10^{−4}$ – $4 \times 10^{−5}$ torr or 0.1–0.005 pascal). Under any of these circumstances is it ...
5
votes
2answers
516 views

How fast do electrons move in an electric arc?

I know that they move extremely slow in wire, http://www.youtube.com/watch?v=jbi7gJTPSXk) but how fast do electrons move in air in an electric spark/arc?
1
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1answer
27 views

What is the deflective efficiency of glass?

If I have ions, electrons, and gas particles bouncing off of glass, how much energy will the particles retain? what % of the energy will be be retained what % lost, the particles I am referring to are ...
0
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1answer
99 views

Energy-temperature relation for electrons in metals

I would like to find the average electron temperature of a metal given the electrons' energy, the density of ions and the electron number density Which models are available, where should I start? Is ...
1
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1answer
60 views

Mass efficiency in electric rocket propulsion?

Why is it more mass efficient to strip away only one electron in electric propulsion even though a double-charged ion is accelerated more than a single-charged ion? Please explain in layperson's ...
1
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1answer
417 views

Refractive index of plasma dependance on temperature

How does the refractive index of plasma changes with temperature? Temperature is not high enough for new ionization. Would it be like in gas p/T dependence ? http://farside.ph.utexas.edu/teaching/em/...
2
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0answers
106 views

Ionospheric electron density measurements

I've been working on measuring total electron column density (TEC) with multi frequency GPS data. In theory, signal delay caused by TEC differences should affect the code and carrier nearly evenly in ...
1
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1answer
168 views

Plasma Question: Expression for electron temperature in terms of the voltage of each prong of a triple Langmuir probe?

So I am trying to derive an expression for electron temperature based on the voltages on a triple Langmuir probe. I have pretty much been following the triple Langmuir probe derivation on wikipedia ...
8
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1answer
1k views

Child-Langmuir space charge law for non-zero cathode potential (non-zero initial electron velocity)

I'm trying to reconcile some conflicting results that I've found in publications that address the idea of the current in a vacuum diode in the case where the cathode has a non-zero potential, in other ...
1
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3answers
403 views

Could I use an electron gun to make plasma?

Could I ionize a gas using an electron gun and knock off electrons in the gas to make plasma?
1
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1answer
83 views

Under what conditions is it possible to ionize atoms using an electron gun?

Using the electron bombardment method, if I wanted to ionize, for example, Xenon gas electrons with an electron gun, under what conditions is it possible to do so? (Heat, pressure?)
5
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1answer
171 views

Special conditions at layer F2 ionosphere

I saw this graph about the electrons density in different altitudes and difference between night and day, the difference between the 2 electron densities (day and night) decreases till 300 Km (F2 ...