About this simulation
The Plasma Globe is a miniature Tesla coil sealed inside a low-pressure glass sphere filled with a noble gas (typically neon, argon, or xenon). A high-frequency, high-voltage electrode at the centre ionises the gas, sending glowing filaments branching outward along the path of least electrical resistance to the glass wall. This simulation reproduces that behaviour in your browser using a GLSL fragment shader — every tendril is computed in real time on the GPU, complete with noise-driven wander and pointer attraction.
🔬 What it shows
Each filament is a conducting plasma channel. The shader models fractional Brownian motion (fBm) noise to make each arc wander independently. As filaments travel outward, the angular width narrows — they become sharp streaks near the glass, just like real plasma. The electrode glow at the centre and the faint rim halo at the glass boundary are also rendered.
🎮 How to use
Drag the Filament count slider (2–12) to add or remove discharge arcs. Intensity / glow brightens the whole globe. Flicker / jitter controls how wildly the tendrils wander — at 0 they are nearly steady, at 1 they thrash chaotically. Switch Colour theme between Electric Blue, Violet, Amber, and Neon Green. Hover or tap anywhere on the globe to bend the nearest filament toward your pointer — imitating a grounded fingertip.
💡 Did you know?
Real plasma globes operate at 2–5 kHz and 2–10 kV. The glass acts as a capacitor: your hand completes the circuit to ground, lowering local impedance so a filament snaps toward it. The effect is why a fluorescent tube held near a plasma globe lights up without being plugged in — the stray electric field is strong enough to ionise the tube's gas.
Frequently asked questions
Why do the filaments bend toward my finger?
Your body acts as a grounded conductor. When you touch (or hover near) the glass, you provide a low-resistance path to ground at that point on the sphere. The electric field intensifies locally, so the nearest plasma filament — always seeking the path of least resistance — deflects toward your fingertip. In this simulation the pointer coordinates are fed directly into the shader uniform uPointerOn, which biases the filament angle calculation toward the pointer direction.
What gas is inside a real plasma globe?
Most commercial plasma globes contain a mixture of noble gases at low pressure (roughly 0.01–0.1 atm). Neon produces orange-red arcs, argon gives violet-blue, xenon produces a bright blue-white, and krypton contributes green tones. The mix is chosen to produce the vivid purple-blue colour most globes display. This simulation lets you explore four colour palettes — Electric Blue, Violet, Amber, and Neon Green — each approximating a different gas or mixture.
What does the Flicker / jitter slider actually change?
It scales the uFlicker uniform, which appears in two places in the GLSL shader: it amplifies the fBm noise that bends each filament's base angle (making arcs wander more), and it increases the depth of the per-filament sinusoidal brightness oscillation (making them flash more intensely). At 0 the arcs are smooth and nearly static; at 1 they writhe and stutter like a real globe with a slightly unstable power supply.
How is the "playful voltage" figure in the Stats panel calculated?
It is a display-only approximation: the simulation maps filament count (2–12) to a voltage range of ~4 kV to ~24 kV in 2 kV steps via a lookup table. Real plasma globes typically run at 2–10 kV, so the numbers are scaled up to feel dramatic. No actual electric field simulation is performed — the filaments are purely visual GLSL arcs driven by fBm noise.
Can I use this simulation to learn about real Tesla coils?
Yes, as a qualitative introduction. The core physics — high-frequency AC from a resonant coil, ionisation of low-pressure gas, discharge filaments following the electric field gradient, and the grounding effect of a nearby conductor — are all accurately represented conceptually. For quantitative study (resonant frequency, Q-factor, primary/secondary coil coupling) you would need a circuit-level simulation, but the visual intuition of plasma behaviour this provides is a solid foundation.