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