Creating an enhanced path to earth by touching the globe increases the strength of the discharge, which is why the arcs are attracted to your hand if you touch the globe.
The alternating voltage at the centre creates electromagnetic waves, and the arcs of plasma act as antennae, meaning that the extent of the electromagnetic field surrounding the ball is significantly larger than the bounds of the glass globe.
Bringing the fluorescent tube near to the plasma ball allows the electrons inside to be accelerated by this field, and those moving electrons constitute an electric current, which causes the bulb to light up. This demonstrates that an electromagnetic wave can be used to accelerate particles, providing an alternative to the large, static voltages supplied by Van de Graaff generators. The color of the light depends on the type of inert gas introduced into the ball, which is usually neon but other options include:.
A current MA candidate in military studies at American Military University, he has written hundreds of articles on a wide range of general science, aviation and history topics. Marker is currently working on several science fiction projects.
How Does a Plasma Ball Work? Related Articles Characteristics of Plasmas. What Are the Colors of Neon? Three Types of Heat Transfers. The radio-frequency energy from the transformer is transmitted into the gas within the globe through an electrode at its center. A much smaller hollow glass orb can also serve as an electrode when it is filled with metal wool or a conducting fluid that is in communication with the transformer output.
In this case, the radio-frequency energy is admitted into the larger space by capacitive coupling right through the glass.
Plasma filaments extend from the inner electrode to the outer glass insulator, giving the appearance of moving tendrils of colored light within the volume of the globe see corona discharge and electric glow discharge. Some globes have a control knob that varies the amount of power going to the center electrode. At the very lowest setting that will light or "strike" the globe, a single tendril is made.
This single tendril's plasma channel engages enough space to transmit this lowest striking energy to the outside world through the glass of the globe. As the power is increased, this single channel's capacity is overwhelmed and a second channel forms, then a third, and so on. The tendrils each compete for a footprint on the inner orb as well.
The energies flowing through these are all of the same polarity so they repel each other as like charges: a thin dark boundary surrounds each footprint on the inner electrode. Placing a finger tip on the glass creates an attractive spot for the energy to flow, because the conductive human body having non-ohmic resistance of about ohms at room temperature is more easily polarized than the dielectric material around the electrode i. Therefore, the capacity of the large conducting body to accept radio frequency energy is greater than that of the surrounding air.
The energy available to the filaments of plasma within the globe will preferentially flow toward the better acceptor. This flow also causes a single filament, from the inner ball to the point of contact, to become brighter and thinner. The filament is brighter because there is more current flowing through it and into the pF capacity, or capacitance, presented by an object, a conducting body, the size of a human.
The filament is thinner because the magnetic fields around it, augmented by the now-higher current flowing through it, causes a magnetohydrodynamic effect called self-focusing: the plasma channel's own magnetic fields create a force acting to compress the size of the plasma channel itself. This shakes the atoms around the wires so hard that their electrons start to fall off! Inside the glass globe is a partial vacuum. This just means that some of the air has been sucked out.
Because there is not as much air in there, it is easier to make electric sparks that can be seen. The electrons then travel out into the air from the glass ball. We know this because the plasma ball lights up the light bulb. If you touch the plasma ball, all of the electrons will go through you to the ground. You see only one big spark inside the ball where you put your hand.
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