All articles starting with H
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Helion Energy
Helion Energy is an American fusion company in Redmond, Washington, developing pulsed field-reversed configuration reactors and signing the first fusion power agreement with Microsoft in 2023.
Helion Polaris
Helion Polaris is the seventh-generation field-reversed configuration fusion prototype of Helion Energy in Everett, Washington, which in February 2026 demonstrated measurable deuterium-tritium fusion at 150 million degrees Celsius.
Helion Venture Partners
Helion Venture Partners is an India-focused venture capital firm founded in 2006, based in Port Louis, Mauritius, that invests in early to mid-stage technology companies such as eCommerce and enterprise software.
Heliopause
The heliopause is the outer boundary of the heliosphere, the sharp surface where the Sun's solar wind is stopped by the interstellar medium about 14 billion kilometers away.
Heliopolis (ancient Egypt)
Heliopolis, ancient Egyptian Iunu (biblical On), was Egypt's principal sun-cult city near Cairo, seat of the Ennead and the benben stone, now largely buried under Matariya with one surviving obelisk of Sesostris I.
Heliopolite Nome
The Heliopolite Nome was the 13th nome of Lower Egypt, an ancient Egyptian administrative district whose capital, Heliopolis, was the principal center of the sun god Ra at the apex of the Nile Delta.
HELIOS
HELIOS (High Energy Laser with Integrated Optical-dazzler and Surveillance) is a 60 kW-class US Navy shipboard laser weapon built by Lockheed Martin, fielded aboard the destroyer USS Preble.
Helios (spacecraft)
Helios was a pair of German-American solar probes, Helios 1 and Helios 2, launched in 1974 and 1976 into orbits carrying them closer to the Sun than any earlier spacecraft.
Helios (Ἥλιος)
Helios (Ἥλιος), Greek sun god, son of Hyperion and Theia, brother of Selene and Eos; little worshiped except on Rhodes (Halieia, Colossus), later conflated with Apollo and adopted by Rome as Sol.
Helios Airways Flight 522
Helios Airways Flight 522, the Helios Airways Disaster, was a Cypriot passenger flight that crashed near Grammatiko, Greece, in 2005, killing all 121 on board.
Helios Capital Management
Helios Capital Management is a Singapore-incorporated, India-focused asset management group founded in 2005 by Samir Arora, running long-short and long-only India equity strategies from Singapore and Mumbai, including Helios Mutual Fund.
Helios Investment Partners
Helios Investment Partners is a London-headquartered private investment firm focused exclusively on Africa, founded in 2004 by Tope Lawani and Babatunde Soyoye, with over $3 billion in assets.
Helios Solar Power Station
The Helios Solar Power Station is a 100 MW parabolic trough solar thermal complex in Ciudad Real, Spain, built by Abengoa and inaugurated in 2012.
Helios-B
Helios-B, also called Helios 2, was a West German–American solar probe launched in January 1976 that held the records for closest approach to the Sun and highest speed until 2018.
Heliosat method
The Heliosat method is a family of algorithms that estimate surface solar irradiance from images taken by geostationary satellites, principally Meteosat, introduced by Cano and colleagues in 1986.
Helioseismology
Helioseismology, also known as solar seismology, is the study of the Sun's interior through its natural modes of oscillation, showing that the solar core rotates about four times faster than the surface.
Heliosheath
The heliosheath is the outer region of the heliosphere where the solar wind slows to subsonic speed against the interstellar medium, first explored by Voyager 1 in 2004.
Heliosphere
The heliosphere is the bubble of magnetized plasma created by the solar wind that encloses the solar system; Voyager 1 and 2 crossed its outer boundary, the heliopause, in 2012 and 2018.
Heliospheric current sheet
The heliospheric current sheet (HCS) is the wavy surface separating oppositely directed solar magnetic field regions, spiraling outward from the Sun with the solar wind.
Heliostat
A heliostat is a mirror that tracks the sun on two axes to reflect sunlight onto a fixed target, as in concentrating solar power towers.
Heliotail
The heliotail is the trailing region of the heliosphere, extending opposite the Sun's motion through the galaxy like a wake, first imaged by NASA's IBEX mission in 2013.
Heliotherapy
Heliotherapy: therapeutic use of natural sunlight, also called climate therapy, for skin disease. Ancient Egyptian and Indian roots; Finsen's 1903 Nobel Prize; Dead Sea regimens for psoriasis; risks include sunburn and skin cancer.
Heliotron E
Heliotron E is a helical magnetic-confinement fusion experiment built by Kyoto University, which began operating in 1980 and achieved a record 2 percent plasma beta for helical systems.
Heliotrope (mineral)
Heliotrope, also called bloodstone, is a dark green variety of chalcedony spotted with red iron-oxide markings resembling drops of blood, long used for seals and signet rings.
Heliotropium
Heliotropium (heliotrope), a genus of about 250 species in Heliotropiaceae (Boraginales) established by Linnaeus in 1753; cosmopolitan herbs and shrubs with scorpioid cymes, pyrrolizidine alkaloids, and C4 species in section Orthostachys.
Heliotropium arborescens
Heliotropium arborescens, garden heliotrope or cherry pie plant (syn. H. peruvianum), is a Boraginaceae subshrub native to Bolivia, Colombia, and Peru, grown for vanilla-scented purple flowers; toxic via pyrrolizidine alkaloids.
Heliox
Heliox is a helium-oxygen breathing gas mixture (typically 70-80% helium) whose low density reduces turbulent airflow resistance in narrowed airways; used for airway obstruction, asthma, COPD, croup, and diving, with limited trial evidence of outcome benefit.
Heliskiing
Heliskiing, also called heli-skiing, is guided backcountry skiing using helicopters as the lift. Pioneered by Hans Gmoser in Canada's Bugaboos in 1965; costs roughly USD$13,000-17,000 weekly, weather-dependent, avalanche-briefed.
Helium
Helium is a chemical element with symbol He and atomic number 2, a colorless, unreactive noble gas and the second most abundant element in the universe.
Helium compounds
Helium compounds are chemical species in which helium binds to other atoms as ions, matrix-trapped species, or high-pressure solids, since neutral helium compounds cannot be formed.