Font size:
Print
Study on Particle Acceleration in Space
Context:
The January 13, 2021 study by researchers from Johns Hopkins University and Northumbria University shed light on the role of collisionless shock waves in accelerating subatomic particles to extreme speeds, addressing a long-standing puzzle in astrophysics.
Key Findings of the study
- Data Sources: NASA’s MMS, THEMIS, and ARTEMIS missions provided critical data on plasma interactions.
- Acceleration Mechanism: The researchers focused on diffusive shock acceleration, where shock waves accelerate electrons. However, a key challenge is the “electron injection problem” — electrons must first reach ~50% of light speed to be further accelerated.
- Significant Observation (Dec 17, 2017):
- High-energy electrons (500 keV) were detected in the foreshock region of Earth’s bow shock.
- Typically, electrons here have just around 1 keV of energy.
- These electrons were moving at ~86% of the speed of light, a surprising and significant leap.
- The acceleration was attributed to a complex interaction of plasma waves and transient structures in the foreshock.
Implications of the Study
- The process might explain the origins of some cosmic rays.
- High-energy electron acceleration could also occur in systems where gas-giant planets orbit very close to their stars.
- This finding hints at a broader mechanism across the universe, potentially redefining how we understand cosmic ray formation.
Future Directions
- The researchers urged the astrophysics and particle acceleration communities to explore and verify this model.
- The study underscores the value of using near-Earth plasma environments as a “natural laboratory” to understand universal phenomena.
