nonthermische

Nonthermische (non-thermal) describes processes or phenomena in which thermal energy is not the primary driver, or where the bulk temperature of the system changes only marginally during the process. The term is used across science and engineering and is often contrasted with thermische (thermal) processes. In practice, non-thermal approaches aim to achieve functional changes without substantial heating.

Non-thermal plasma refers to partially ionized gas in which electrons reach high temperatures while the heavy species remain near ambient temperatures. This allows chemical reactions at or near room temperature and is used for sterilization, surface modification, and materials processing without bulk heating. Key features include high electron energy, non-Maxwellian distributions, and reactive radicals produced by electric or microwave discharges.

In food processing, non-thermal technologies seek microbial inactivation without significant temperature rise. Examples include high-pressure processing, pulsed electric fields, ultraviolet irradiation, irradiation, and cold plasma treatments. Benefits include nutrient and flavor preservation and reduced quality loss, but challenges include equipment costs, process validation, and regulatory approval.

In physics and astronomy, non-thermal radiation is radiation not described by a blackbody spectrum. It often results from energetic particles and processes such as synchrotron emission or inverse Compton scattering, yielding power-law spectra. The concept helps distinguish emissions tied to particle acceleration from thermal emission of objects in equilibrium.