# Lightning

> Comprehensive lightning physics knowledge base derived from Rakov & Uman (2003) "Lightning: Physics and Effects". Covers discharge types, current parameters, leader/return-stroke physics, cloud electrification, protection, detection systems, atmospheric effects, and quantitative reference data. Use when answering questions about lightning physics, electromagnetic fields, thunderstorm electricity, lightning protection, or atmospheric electrical phenomena.

- Skill: `kjanat/lightning` (Agent Skill, multi-file: 30 files)
- Install (CLI): `npx skillmds@latest add kjanat/lightning`
- Raw SKILL.md: https://api.skillmd.com/api/skills/kjanat/lightning/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- License: MIT
- Author: kjanat (https://skillmd.com/u/kjanat)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/kjanat/lightning

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# Lightning Physics Knowledge Base

Quantitative reference on lightning physics, effects, and protection. All data
from Rakov & Uman (2003) unless noted.

## Reading Order

| Task                                            | File                                        |
| ----------------------------------------------- | ------------------------------------------- |
| Lightning types, terminology, global circuit    | `references/types-terminology-circuit.md`   |
| Flash rates, density, geographic distribution   | `references/incidence-statistics.md`        |
| Thundercloud charge structure, electrification  | `references/cloud-electrification.md`       |
| Stepped leader physics                          | `references/stepped-leader.md`              |
| Return stroke currents, speed, channel, fields  | `references/return-stroke.md`               |
| Dart leader, continuing current, M-components   | `references/dart-leader-m-component.md`     |
| Positive CG lightning and bipolar flashes       | `references/positive-lightning.md`          |
| Upward lightning from tall structures           | `references/upward-lightning.md`            |
| Rocket-triggered lightning                      | `references/triggered-lightning.md`         |
| Cloud discharges and winter lightning           | `references/cloud-winter-discharges.md`     |
| Aircraft interaction and thunder                | `references/aircraft-thunder.md`            |
| Return stroke modeling (engineering + physical) | `references/return-stroke-models.md`        |
| Sferics, Schumann resonances, whistlers         | `references/distant-em-signals.md`          |
| Sprites, elves, blue jets, TGFs                 | `references/upper-atmosphere-tles.md`       |
| NOx production, extraterrestrial lightning      | `references/chemistry-extraterrestrial.md`  |
| Lightning locating systems (NLDN, satellite)    | `references/locating-systems.md`            |
| Protection methods, grounding, standards        | `references/protection-standards.md`        |
| Human hazards, safety, ball lightning           | `references/human-hazards-unusual.md`       |
| Cross-study statistical tables (Berger, Rakov)  | `references/detailed-statistical-tables.md` |

## Quick Reference: Key Parameters

### Flash Structure

| Parameter                    | Typical Value    |
| ---------------------------- | ---------------- |
| Strokes per flash            | 3-5 (range 1-26) |
| Flash duration               | 200-300 ms       |
| Interstroke interval         | 60 ms            |
| Total charge per flash       | 20 C             |
| Energy per flash             | 10^9-10^10 J     |
| Single-stroke flashes        | 15-20%           |
| Multiple ground terminations | ~50% of flashes  |

### Current Parameters (Berger et al. 1975)

| Parameter                     | First Stroke (median) | Subsequent (median) |
| ----------------------------- | --------------------- | ------------------- |
| Peak current                  | 30 kA                 | 12 kA               |
| Max dI/dt                     | 12 kA/us              | 40 kA/us            |
| Front duration (2 kA to peak) | 5.5 us                | 1.1 us              |
| Duration (to half-peak)       | 75 us                 | 32 us               |
| Impulse charge                | 4.5 C                 | 0.95 C              |
| Action integral               | 5.5x10^4 A^2s         | 6.0x10^3 A^2s       |

### Process Speeds

| Process          | Speed (m/s)             |
| ---------------- | ----------------------- |
| Stepped leader   | 2x10^5 (average)        |
| Dart leader      | 10^7 (typical)          |
| Return stroke    | (1-2)x10^8 (c/3 to c/2) |
| M-component wave | (2.5-3)x10^7            |

### Channel Properties

| Property         | Value                   |
| ---------------- | ----------------------- |
| Peak temperature | 28,000-31,000 K         |
| Peak pressure    | ~8 atm (first 5 us)     |
| Electron density | 8x10^17 cm^-3 (at 5 us) |
| Channel radius   | 1-4 cm                  |
| Conductivity     | ~10^4 S/m               |

### Lightning Types

| Type                 | Fraction            | Notes                                  |
| -------------------- | ------------------- | -------------------------------------- |
| Downward negative CG | ~90% of CG          | Most common                            |
| Downward positive CG | <10% of CG          | Higher peak currents at extremes       |
| Cloud discharges     | ~75% of all         | Intracloud, intercloud, cloud-to-air   |
| Upward (neg + pos)   | From >100 m objects | Only from tall structures/mountaintops |

### Global Statistics

| Quantity                        | Value                                      |
| ------------------------------- | ------------------------------------------ |
| Global flash rate               | 45 +/- 5 per second (satellite)            |
| Cloud:CG ratio (z)              | ~3 average (range 1-10+)                   |
| Land:ocean flash ratio          | ~7.7                                       |
| Active thunderstorms (any time) | ~2000                                      |
| US annual CG flashes            | ~25 million                                |
| US flash density range          | 0.1 (Pacific) to >14 (Florida) km^-2 yr^-1 |

### Positive Lightning Extremes

| Parameter       | 50%           | 5%            |
| --------------- | ------------- | ------------- |
| Peak current    | 35 kA         | 250 kA        |
| Charge transfer | 80 C          | 350 C         |
| Action integral | 6.5x10^5 A^2s | 1.5x10^7 A^2s |

## Computational Tools

| Script                            | Contents                                                              |
| --------------------------------- | --------------------------------------------------------------------- |
| `scripts/leader_fields.py`        | Stepped-leader E/B field (Eq 4.1-4.7), retarded height                |
| `scripts/return_stroke_models.py` | Engineering models (TL/MTLL/MTLE/BG/TCS), Heidler, Braginskii         |
| `scripts/thunder.py`              | Few's theory (R_0, f_m), flash-to-bang, N-wave overpressure           |
| `scripts/schumann.py`             | Schumann resonance frequencies, whistler dispersion, Wait-Spies       |
| `scripts/protection.py`           | Striking distance, rolling sphere, grounding resistance, step voltage |
| `scripts/m_component.py`          | M-component two-wave model (Eq 12.7-12.8), source pulse               |
| `scripts/incidence.py`            | Ng-Td/Th formulas, structure incidence, Poisson probability           |

All scripts use stdlib only (`math`, `enum`). Each has a `__main__` demo block.