Plasma Colors: Temperature, Composition & Astrophysical Context

Color-Temperature Correlation in Plasma

Plasma color is primarily determined by temperature (via black-body radiation and spectral line emission) and composition (ion species). The following are approximate visual color ranges for common astrophysical and laboratory plasmas:

Color	Approx. Temperature	Typical Environments
Blue	~10,000–20,000 K	Solar photosphere, fusion reactors, Earth's aurora (lower altitude)
Red	~20,000–30,000 K	Solar chromosphere, certain gas discharges (H-alpha emission)
Orange	~30,000–50,000 K	Upper chromosphere, some planetary nebulae
Yellow	~50,000–70,000 K	Solar transition region, corona of some stars
White	~100,000 K+	Hot stars (O-type), white dwarfs, supernova remnants
Blue-White	~200,000 K+	Very hot stars, active galactic nuclei (AGN) cores

Important Notes

• Colors are based on visual perception and can vary with viewing conditions, instrument filters, and mixed emission lines.
• Non-thermal plasmas (e.g., neon signs, fluorescent lights) produce colors via specific atomic transitions, not black-body radiation.
• In fusion research, plasma color helps diagnose temperature and impurity levels.