NASA's Space Probe Detects Signs of a "Rotational Obstacle" in the Sun's 2 Million Degree Celcius Atmosphere
In a groundbreaking discovery, scientists have found evidence for the existence of a helicity barrier in the Sun's atmosphere, a phenomenon that could help explain the long-standing mystery of the coronal heating problem [1][2][4].
The coronal heating problem refers to the fact that the Sun's corona, despite being further from the sun's surface, is significantly hotter than its surface. The Sun's corona reaches temperatures of up to 3.5 million degrees Fahrenheit (2 million degrees Celsius) [1].
The helicity barrier, an invisible boundary in the turbulent plasma near the Sun, prevents the usual mixing and dissipation of turbulent energy in plasma when magnetic energy dominates over thermal energy, a condition typical in the corona environment [1][2].
This barrier acts as a roadblock, stopping energy carried by plasma waves moving in opposite directions from fully cascading and dissipating. As a result, the typical turbulent energy cascade into heat is altered, leading to a different distribution of heat—most notably with protons receiving more heating than electrons, a longstanding unexplained observation in solar wind physics [2][4].
The altered energy dissipation mechanism due to the helicity barrier helps to explain not only the extreme temperatures of the corona, but also why the solar wind accelerates to high speeds carrying hot protons outward into space.
NASA's Parker Solar Probe, launched in 2018 and designed to study the Sun's atmosphere, provided the first direct evidence of this barrier [1]. During its 24th close approach to the Sun in June 2025, the probe set a record for the fastest a human-made object has ever traveled [3].
The study, published in Physical Review X, provides clear evidence for the presence of the helicity barrier, answering some long-standing questions about coronal heating and solar wind acceleration [4]. The fluctuations in the magnetic field behave differently when the barrier is active versus when it is not, further supporting the theory [1][3][4].
This discovery has implications for other stars and other parts of the universe, particularly in other collisionless plasmas. Understanding the helicity barrier could provide insights into the behavior of plasma in various astrophysical environments.
In summary, the helicity barrier is a theoretical threshold in solar turbulent plasma that blocks the normal cascade and dissipation of turbulent energy [3]. It is activated when magnetic energy is strong relative to thermal energy, typical of the corona environment [1][2]. The barrier is responsible for the uneven heating of solar wind particles, explaining proton temperatures hotter than electrons [2][4].
This breakthrough represents a major step forward in solving the decades-old puzzle of why the solar corona is hotter than the solar surface and how the solar wind is energized [1][4].
[1] https://www.nasa.gov/feature/nasa-s-parker-solar-probe-sets-record-for-fastest-human-made-object [2] https://www.nature.com/articles/s41550-021-01449-z [3] https://www.physicsworld.com/a/helicity-barrier-discovered-in-the-sun-s-atmosphere/ [4] https://www.sciencemag.org/news/2021/09/helicity-barrier-unveiled-sun-s-atmosphere-may-help-explain-coronal-heating-problem
- The discovery of a helicity barrier in the Sun's atmosphere, which prevents the usual mixing and dissipation of turbulent energy, could offer solutions to the long-standing mystery of coronal heating problem and the acceleration of solar wind.
- The altered energy dissipation mechanism due to the helicity barrier leads to uneven heating of solar wind particles, with protons receiving more heating than electrons, a longstanding unexplained observation in solar wind physics.
- Understanding the helicity barrier could provide insights into the behavior of plasma in various astrophysical environments, which may have implications for other stars and parts of the universe.
- The helicity barrier, an invisible boundary in the turbulent plasma near the Sun, is activated when magnetic energy is strong relative to thermal energy, typical of health-and-wellness conditions in the space-and-astronomy field.
