Task 356: EP02 Jupiter Radiation Belt Quantitative Analysis

Status: DONE

Description

EP02 mentions "放射線シールドの残寿命42分" as a constraint on Jupiter escape, but the current analysis treated this qualitatively. This task adds a quantitative radiation dose model for the Jupiter magnetosphere transit.

Results

Key Finding: Shield survival requires active acceleration

Scenario	Avg radial v	Transit time	Accumulated dose	Shield budget	Survives?
Passive escape	7 km/s	99.4 h	0.310 krad	0.043 krad	NO (7.2× over)
Brachistochrone	60 km/s	11.6 h	0.036 krad	0.043 krad	YES (84%)
Damaged (20 km/s)	20 km/s	34.8 h	0.109 krad	0.043 krad	NO (2.5× over)
High-latitude	7 km/s	99.4 h	0.047 krad	0.043 krad	NO (8% over)

Minimum survival velocity: ~50.4 km/s (average radial component)

Physical interpretation

"42分" = shield dose budget remaining / instantaneous dose rate at 15 RJ. As the ship moves outward, dose rate drops steeply (540× between Ganymede and Callisto), so the shield effectively "heals" — but only if the ship passes through the belt quickly enough. Passive coast takes too long.

Codex consultation (gpt-5.2)

Consulted on model design. Key recommendations adopted:

Piecewise power-law with analytical integration (closed-form, no numerical integrator)
"42 min" = dose_budget / current_rate interpretation
Geometry/variability multipliers (latitude, plasma sheet, storm)
Magnetopause cutoff at 63 RJ

Implementation

20 Rust tests in jupiter_radiation.rs (all pass)
Piecewise power-law model calibrated to Galileo DDD values
Analytical dose integration per segment (no numerical quadrature)
TypeScript mirror in ep02-analysis.ts for calculation output
EP02 report new exploration ep02-exploration-07
Content validation test for the new exploration

Files

crates/solar-line-core/src/jupiter_radiation.rs — radiation belt dose model (20 tests)
ts/src/ep02-analysis.ts — TypeScript radiation analysis + calculation output
ts/src/article-content-validation.test.ts — EP02 radiation content test
reports/data/episodes/ep02.md — ep02-exploration-07 (radiation analysis)
reports/data/calculations/ep02_calculations.json — jupiterRadiation section