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Space Physics and Heliophysics
Space physics and heliophysics includes the study of the Sun and the solar wind and their interactions with the magnetospheres of Earth and the other planets and comets. A primary goal is to understand how human society, technological systems, and the habitability of planets are affected by solar variability interacting with planetary magnetic fields and atmospheres.
The Sun ejects a continuous supersonic stream of charged particles called the “solar wind.” The solar wind carves out an extended “bubble” in the interstellar medium called the “heliosphere” -- the sphere of influence of the Sun- extending well beyond the planets. JPL’s Mariner 2 spacecraft, launched in 1962, measured for the first time, the properties of this fast tenuous gas of charged particles – electrons and ions. The Ulysses Mission, now in its 18th year, was the first to study the three-dimensional structure of the solar magnetic fields and the heliosphere. Now, JPL’s twin Voyager spacecraft, launched in 1977, are the first to venture to the edge of the heliosphere and study the interaction of the solar wind with the surrounding interstellar medium.
Currently, JPL is involved in a number of programs and missions in this research area that explore the Sun, the solar wind, and the magnetospheres of Earth and planets and comets. Research activities involve theory, instrumentation, space and ground-based observations, data analysis and laboratory studies.
Selected Current Research Projects
The dual mode Vector/Scalar Helium Magnetometer (V/SHM) instrument, flown on the Cassini mission, has provided new scientific information about Saturn's magnetic field.
Ulysses’ magnetometer, used to study the three-dimension structure of the solar magnetic fields in the heliosphere, was developed by JPL scientists. Analysis of the magnetometer data from Ulysses has revolutionized our understanding of the solar magnetic fields permeating the heliosphere. To study Saturn’s magnetic field, the Cassini mission also carried a magnetometer developed at JPL.
JPL scientists are analyzing data from NASA’s two-spacecraft Solar Terrestrial Relations Observatory (STEREO) mission. The two STEREO spacecraft are in 1 AU heliocentric orbits drifting away from Earth - one leading and one lagging - at 22 degrees per Earth year. The focus of this mission is to understand massive solar storms called coronal mass ejections or CMEs. Each spacecraft carries five telescopes, which can image the heliosphere from the Sun to Earth. The panorama below shows the fields of view of seen by each spacecraft – from the Sun at the center out to Earth at the left and right edges.
Composite images of the views from the five telescopes on each STEREO spacecraft. Three telescopes point directly at the Sun; two Heliospheric Imagers cover the sky from the Sun to Earth (both edges of the panorama). The Milky Way can be seen in STEREO B’s field of view.
Compact Doppler/Magnetograph for Solar Diagnostics
JPL scientists are working on the development of instruments that measure velocity and magnetic fields in the sun’s chromosphere and photosphere, known as Doppler magnetographs. The instrument concept is based on the magneto-optical filter, which can be designed to have very narrow pass-bands in several useful solar absorption lines. The image below shows an example of data from such an instrument – it shows an intensity image on the left, a velocity image in the center and an image of the line-of-sight magnetic field on the right. The cutout below shows details of the highly structured solar magnetic field in the vicinity of two small sunspots. Doppler magnetographs are used for both ground and space-based observations: our group is developing a flight version of the instrument that will be a factor of 10 lighter than current flight instruments.
Example of data from a Doppler magnetograph, operating at JPL showing intensity, velocity, and line-of-sight magnetic field in the Sun's photosphere.