^2}{v_m^2}\right)\left(\frac{a}{r}\right) - 4\ln\left(\frac{v_{\text{esc^2}{v_m^2}\right) - 3 + \ln 256</math>

One solution to this equation was immediately recognizable as a solar wind.

Parker's theory of supersonic solar wind also predicted the shape of the solar magnetic field in the outer Solar System. Parker argued that a million-degree corona cannot remain static: pressure forces must drive a radially expanding flow that accelerates from subsonic near the Sun to supersonic beyond a critical point. He further noted that solar rotation winds outward-advected magnetic field lines into a spiral pattern in the ecliptic, now called the Parker spiral. At the time, no spacecraft took measurements of space medium, and Parker himself was an unknown 31-year-old professor from Chicago. Chamberlain's subsonic solution was called the "solar breeze".

Parker wrote to his parents about the solar wind theory rejection:

Parker's theoretical predictions were confirmed by satellite observations: in 1959, the flow of particles from the Sun was detected by the Soviet's Luna 2. In 1962, four years after the original publication, Mariner 2 mission carried out observations with a specifically designed instrument. It is called to be "a unique example in astrophysics, due to its immediate and brief confirmation by observations". Mariner 2 data revealed two types of solar wind, a low- and a high-speed components.

1972–1988: Coronal heating and nanoflares

thumb|A close-up of one of the loop brightenings. The frame on the far right is the most zoomed in, showing the putative nanoflare.

Parker argued that random footpoint motions in the photosphere inevitably tangle coronal fields, making smooth equilibria topologically unattainable. The corona relaxes via ubiquitous current sheets where reconnection dissipates energy, supplying heat. Initial skepticism gave way to broader interest as stellar coronal X-rays were established; Parker then estimated the energy budget and introduced the nanoflare concept—many small events rather than single large releases. The field converged on a mixed picture: closed-loop regions likely dominated by current-sheet heating; open-field regions more wave-driven.

Parker Solar Probe

In 1960, a Space Science Board report recommended a solar spacecraft mission to study the origins of solar wind, and another mission to the outer Solar System "to study the interaction of the heliosphere with the interstellar medium". In 2010, NASA approved the Solar Probe Plus mission; Parker was invited as an advisor.

In 2017, NASA renamed the Solar Probe Plus to Parker Solar Probe in Parker's honor, the first NASA spacecraft named after a living person. In October 2017, Parker visited the spacecraft at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. In 2018, Parker and his family traveled to Cape Canaveral to watch the PSP's launch.

Parker Solar Probe used repeated gravity assists from Venus to develop an eccentric orbit, approaching within 9.86 solar radii (6.9 million km or 4.3 million miles) from the center of the Sun. At its closest approach in 2024, its speed relative to the Sun was or 191 km/s (118.7 mi/s), which is 0.064% <!-- Do NOT "correct" this figure. 0.064% IS CORRECT. Notice the percent sign; 0.00064 EQUALS 0.064%. If this is not clear, please see the discussions on the Talk Page. --> the speed of light. It is the fastest object ever built on Earth. PSP is the first spacecraft that entered the solar atmosphere, which was described by NASA as "touching the Sun". It was done when PSP passed the Alfven surface which marks the end of the solar atmosphere and beginning of the solar wind.

Personal life

Parker met his future wife, Niesje, in Utah. Her family was from the Netherlands; she emigrated to the US after World War II. She had a degree in bacteriology. They married in 1954. In Chicago, Niesje got a job at the University of Chicago Graduate School of Business, and later became an Associate Director of Computing Services. His body was cremated, and half of the ashes buried near his log cabin in the woods.

  • 1969: Henry Norris Russell Lectureship of the American Astronomical Society
  • 1978: George Ellery Hale Prize, Solar Physics Division of the American Astronomical Society, first time this prize was awarded
  • 1979: Chapman Medal of the Royal Astronomical Society
  • 1989: National Medal of Science
  • 1990: William Bowie Medal
  • 1997: Bruce Medal
  • 2003: James Clerk Maxwell Prize of the American Physical Society "For seminal contributions in plasma astrophysics, including predicting the solar wind, explaining the solar dynamo, formulating the theory of magnetic reconnection, and the instability which predicts the escape of the magnetic fields from the galaxy."
  • 2010: Member of the Norwegian Academy of Science and Letters.
  • 2017: NASA renamed its Solar Probe Plus mission to Parker Solar Probe, the first time that a spacecraft was named after a living person.
  • 2020: Crafoord Prize in Astronomy

Selected publications

; Scientific articles

; Books

  • .

; Other articles

Notes

References

</references>

  • Preface to special topic: Plasma physics of the Sun in honor of Eugene Parker