The heliosphere is the magnetosphere, astrosphere, and outermost atmospheric layer of the Sun. It takes the shape of a vast, tailed bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding interstellar medium. The "bubble" of the heliosphere is continuously "inflated" by plasma originating from the Sun, known as the solar wind. Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating the Milky Way. As part of the interplanetary magnetic field, the heliosphere shields the Solar System from significant amounts of cosmic ionizing radiation; uncharged gamma rays are, however, not affected. Its name was likely coined by Alexander J. Dessler, who is credited with the first use of the word in the scientific literature in 1967. The scientific study of the heliosphere is heliophysics, which includes space weather and space climate.
The interplanetary medium (IPM) or interplanetary space consists of the mass and energy which fills the Solar System, and through which all the larger Solar System bodies, such as planets, dwarf planets, asteroids, and comets, move. The IPM stops at the heliopause, outside of which the interstellar medium begins. Before 1950, interplanetary space was widely considered to either be an empty vacuum, or consisting of "aether".
The Committee on Space Research (COSPAR) was established on October 3, 1958 by the International Council for Scientific Unions (ICSU) and its first chair was Hildegard Korf Kallmann-Bijl. Among COSPAR's objectives are the promotion of scientific research in space on an international level, with emphasis on the free exchange of results, information, and opinions, and providing a forum, open to all scientists, for the discussion of problems that may affect space research. These objectives are achieved through the organization of symposia, publication, and other means. COSPAR has created a number of research programmes on different topics, a few in cooperation with other scientific Unions. The long-term project COSPAR international reference atmosphere started in 1960; since then it has produced several editions of the high-atmosphere code CIRA. The code "IRI" of the URSI-COSPAR working group on the International Reference Ionosphere was first edited in 1978 and is yearly updated.
Solar physics is the branch of astrophysics that specializes in the study of the Sun. It intersects with many disciplines of pure physics and astrophysics.
The following outline is provided as an overview of and topical guide to astronomy:
The Journal of Geophysical Research is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the understanding of the Earth, Sun, and Solar System. It has seven sections: A, B, C (Oceans), D (Atmospheres), E (Planets), F, and G (Biogeosciences). All current and back issues are available online for subscribers.
Interstellar Boundary Explorer is a NASA satellite in Earth orbit that uses energetic neutral atoms (ENAs) to image the interaction region between the Solar System and interstellar space. The mission is part of NASA's Small Explorer program and was launched with a Pegasus-XL launch vehicle on 19 October 2008.
Space physics, also known as space plasma physics, is the study of naturally occurring plasmas within Earth's upper atmosphere and the rest of the Solar System. It includes the topics of aeronomy, aurorae, planetary ionospheres and magnetospheres, radiation belts, and space weather. It also encompasses the discipline of heliophysics, which studies the solar physics of the Sun, its solar wind, the coronal heating problem, solar energetic particles, and the heliosphere.
Heliophysics is the physics of the Sun and its connection with the Solar System. NASA defines heliophysics as "(1) the comprehensive new term for the science of the Sun - Solar System Connection, (2) the exploration, discovery, and understanding of Earth's space environment, and (3) the system science that unites all of the linked phenomena in the region of the cosmos influenced by a star like our Sun."
The Heliophysics Science Division of the Goddard Space Flight Center (NASA) conducts research on the Sun, its extended Solar System environment, and interactions of Earth, other planets, small bodies, and interstellar gas with the heliosphere. Division research also encompasses geospace—Earth's uppermost atmosphere, the ionosphere, and the magnetosphere—and the changing environmental conditions throughout the coupled heliosphere.
David John McComas is an American space physicist, Professor of Astrophysical Sciences, and leads the Space Physics at Princeton Group at Princeton University. He was the Princeton University Vice President for the Princeton Plasma Physics Lab (PPPL) from 2016 - 2024 and previously Assistant Vice President for Space Science and Engineering at the Southwest Research Institute, Adjoint Professor of Physics at the University of Texas at San Antonio (UTSA), and was the founding director of the Center for Space Science and Exploration at Los Alamos National Laboratory. He is noted for his extensive accomplishments in experimental space plasma physics, including leading instruments and missions to study the heliosphere and solar wind: IMAP, IBEX, TWINS, Ulysses/SWOOPS, ACE/SWEPAM, and Parker Solar Probe. He received the National Academy of Science's 2023 Arctowski Medal, European Geosciences Union 2022 Hannes Alfven Medal, SCOSTEP 2022 Distinguished Scientist Award, a NASA Exceptional Public Service Medal in 2015, the 2014 COSPAR Space Science Award, and the American Geophysical Union 1993 Macelwane Medal.
Barbara June Thompson is an American solar physicist. She is a scientist at Goddard Space Flight Center where she researches coronal mass ejections and the dynamics of coronal structures. Thompson was the project scientist for NASA's Solar Dynamics Observatory mission through development and early flight.
In solar physics, heliospheric pickup ions are created when neutral particles inside the heliosphere are ionized by either solar ultraviolet radiation, charge exchange with solar wind protons or electron impact ionization. Pickup ions are generally characterized by their single charge state, a typical velocity that ranges between 0 km/s and twice the solar wind velocity (~800 km/s), a composition that reflects their neutral seed population and their spatial distribution in the heliosphere. The neutral seed population of these ions can either be of interstellar origin or of lunar-, cometary, or inner-source origin. Just after the ionization, the singly charged ions are picked up by the magnetized solar wind plasma and develop strong anisotropic and toroidal velocity distribution functions, which gradually transform into a more isotropic state. After their creation, pickup ions move with the solar wind radially outwards from the Sun.
The Interstellar Mapping and Acceleration Probe(IMAP) is a heliophysics mission that will simultaneously investigate two important and coupled science topics in the heliosphere: the acceleration of energetic particles and interaction of the solar wind with the local interstellar medium. These science topics are coupled because particles accelerated in the inner heliosphere play crucial roles in the outer heliospheric interaction. In 2018, NASA selected a team led by David J. McComas of Princeton University to implement the mission, which is currently scheduled to launch on 29 April 2025. IMAP will be a Sun-tracking spin-stabilized satellite in orbit about the Sun–Earth L1 Lagrange point with a science payload of ten instruments. IMAP will also continuously broadcast real-time in-situ data that can be used for space weather prediction.
NASA's Solar Terrestrial Probes program (STP) is a series of missions focused on studying the Sun-Earth system. It is part of NASA's Heliophysics Science Division within the Science Mission Directorate.
Space climate is the long-term variation in solar activity within the heliosphere, including the solar wind, the Interplanetary magnetic field (IMF), and their effects in the near-Earth environment, including the magnetosphere of Earth and the ionosphere, the upper and lower atmosphere, climate, and other related systems. The scientific study of space climate is an interdisciplinary field of space physics, solar physics, heliophysics, and geophysics. It is thus conceptually related to terrestrial climatology, and its effects on the atmosphere of Earth are considered in climate science.
Eckart Marsch is a German theoretical physicist, who worked from 1980 to 2012 at the originally named Max Planck Institute for Aeronomy, from 2004 on named Max Planck Institute for Solar System Research (MPS) in Katlenburg-Lindau on the physics of the solar wind, solar corona and space plasmas and taught at the University of Göttingen.
George L. Siscoe was an American physicist and professor emeritus of space physics at Boston University. He made major contributions to the understanding of the Earth's magnetosphere and the heliosphere, particularly in helping to establishing the field of space weather and the term heliophysics - a term which is now standard use.
Dr Natchimuthuk "Nat" Gopalswamy is an Indian American Solar physicist. He is currently a staff scientist at the Heliophysics Division of NASA’s Goddard Space Flight Center.
The Solar and Space Physics Decadal Survey is a publication of the National Research Council produced for NASA, as well as other US government agencies such as NOAA and the National Science Foundation. It is produced with the purpose of identifying a recommended scientific strategy in the field of heliophysics for the following decade. Agencies such as NASA utilize the decadal survey in order to prioritize funding for specific missions or scientific research projects.
