What is impeadence of ionized air?

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In summary: According to the article, spark gaps have very low impedances, and are often used in electrical systems to switch large amounts of power. There are also plans available online for building your own spark gap.
  • #1
Agnostic
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what is impeadence of ionized air?
 
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  • #2
I've done some google and wiki searching, but I didn't find a good link. Basically, when you have a full-on arc, the impedance is very low (like a wire). The terms to search on are ionization, glow, arc, spark, etc. Spark gap protection devices for data line networks are basically short circuits when they arc over.
 
  • #3
berkeman said:
I've done some google and wiki searching, but I didn't find a good link. Basically, when you have a full-on arc, the impedance is very low (like a wire). The terms to search on are ionization, glow, arc, spark, etc. Spark gap protection devices for data line networks are basically short circuits when they arc over.


I found one research article in journal of chemistry that says it is 1gigaohm AFTER ionization...which is luidicris(sp?)...
 
  • #4
Agnostic said:
I found one research article in journal of chemistry that says it is 1gigaohm AFTER ionization..

Depends also on how much ionisation.

In fact, an arc is badly described by an impedance, because the V-I relationship is highly non-linear (while impedance would be the linear coefficient). As berkeman said, for a strong arc, the differential impedance can be near zero (almost no change in V for a change in I).
 
  • #5
Also, unlike most materials, impedance of air decreases as temperature increases. So a spark that we see as an instantaneous eventis actually a fairly complex process. A little bit of current jumps a gap once the air is sufficiently ionized, and this currwent encounters strong resistance. The passage of current through resistance creates heat (which further ionizes the air, I believe), and causes more current to flow.
 
  • #6
A couple more things that needs to be taken into account are air pressure and humidity. These things can change the resistance of air quite dramatically
 
  • #7
Emicro said:
A couple more things that needs to be taken into account are air pressure and humidity. These things can change the resistance of air quite dramatically


assuming STP
 
  • #8
With proper design, spark gaps can have very low impedances, though I'm afraid I don't know the details of what's required to accomplish this. Devices apparently exist that can switch mega-amperes (with kilovolts power supplies).

Some web references:

http://jamsci.org/2003-10-12/0007/SparkGapTubeArticle.html

(has a bibliography to some literature on the topic, and a quick overview of some of the physics involved, which is considerable).

http://www.amazing1.com/sparkgap.htm

sells a railgun spark gap switch, but wants a lot of money for the plans (don't know if they are on the up-and-up).

http://en.wikipedia.org/wiki/Spark_gap#Power-switching_devices

wikipedia article about spark gaps.
 
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1. What is impedance of ionized air?

Impedance of ionized air refers to the resistance that ionized air presents to the flow of electric current. It is affected by factors such as temperature, humidity, composition of the air, and the presence of other ions or particles.

2. How is impedance of ionized air measured?

Impedance of ionized air can be measured using instruments such as a high-voltage power supply, an electrometer, and a Faraday cage. The power supply generates a known voltage, and the electrometer measures the current passing through the Faraday cage, which is used to calculate the impedance.

3. What are the effects of ionized air on electrical equipment?

Ionized air can cause electrical equipment to malfunction or fail due to the presence of charged particles, which can disrupt the flow of electricity and cause damage to sensitive components. It can also create high levels of static electricity, which can damage electronic devices.

4. How does ionized air affect human health?

Ionized air can have both positive and negative effects on human health. On one hand, it can help to remove harmful particles from the air, making it easier to breathe. On the other hand, exposure to high levels of ionized air can cause irritation to the respiratory system and aggravate conditions such as asthma.

5. Can impedance of ionized air be controlled?

Yes, the impedance of ionized air can be controlled through various methods such as using air filters, humidifiers, and dehumidifiers to regulate the composition and humidity of the air. Additionally, grounding techniques can be used to reduce the build-up of static electricity and mitigate the effects of ionized air on electrical equipment.

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