Sun-Earth Interaction Research Articles

Modeling the young Sun's solar wind and its interaction with Earth's paleomagnetosphere

We present a focused parameter study of solar wind - magnetosphere interaction for the young Sun and Earth, $~3.5$ Ga ago, that relies on magnetohydrodynamic (MHD) simulations for both the solar wind and the magnetosphere. By simulating the quiescent young Sun and its wind we are able to propagate the MHD simulations up to Earth's magnetosphere and obtain a physically realistic solar forcing of it. We assess how sensitive the young solar wind is to changes in the coronal base density, sunspot placement and magnetic field strength, dipole magnetic field strength and the Sun's rotation period. From this analysis we obtain a range of plausible solar wind conditions the paleomagnetosphere may have been subject to. Scaling relationships from the literature suggest that a young Sun would have had a mass flux different from the present Sun. We evaluate how the mass flux changes with the aforementioned factors and determine the importance of this and several other key solar and magnetospheric variables with respect to their impact on the paleomagnetosphere. We vary the solar wind speed, density, interplanetary magnetic field strength and orientation as well as Earth's dipole magnetic field strength and tilt in a number of steady-state scenarios that are representative of young Sun-Earth interaction. This study is done as a first step of a more comprehensive effort towards understanding the implications of Sun-Earth interaction for planetary atmospheric evolution.

Space Weather: Physics, Effects and Predictability

The time varying conditions in the near-Earth space environment that may affect space-borne or ground-based technological systems and may endanger human health or life are referred to as space weather. Space weather effects arise from the dynamic and highly variable conditions in the geospace environment starting from explosive events on the Sun (solar flares), Coronal Mass Ejections near the Sun in the interplanetary medium, and various energetic effects in the magnetosphere–ionosphere–atmosphere system. As the utilization of space has become part of our everyday lives, and as our lives have become increasingly dependent on technological systems vulnerable to the space weather influences, the understanding and prediction of hazards posed by these active solar events have grown in importance. In this paper, we review the processes of the Sun–Earth interactions, the dynamic conditions within the magnetosphere, and the predictability of space weather effects on radio waves, satellites and ground-based technological systems today.

Sun-Earth Interaction and its impact in the upper atmosphere

Sun-Earth Interaction and its impact in the upper atmosphere

Monitoring of atmospheric changes related to sun-earth interactions

Our upper atmosphere is affected by solar forcing, whose main sources are the ionizing radiation and space weather. The solar ionizing radiation changes in association with the 11-year solar cycle, 27-day rotation and solar flares. VLF soundings have confirmed the solar Lyman-alpha as responsible through the formation and maintenance of the ionized layer of our atmosphere, the ionosphere, which shows variations in close association with the 11-year solar cycle. Excess of X-ray radiation produced during the solar flares, when the solar radiation can increase in order of magnitude, strongly disturbs the lower ionosphere. Ionosphere studies using VLF technique have identified that even very weak solar flares (B2 as X-ray classification from GOES satellite) can be enough to affect the ionosphere during the minimum of solar activity, but this limit increases as the Sun becomes more active. The ionosphere is also affected by forcing coming from the lower-lying atmospheric layers. The influence of the planetary waves of neutral atmosphere origin has been observed, and it is dominant during the local wintertime. The studies have shown the influence of the Sun-earth interaction in the chemistry and dynamics of our atmosphere, and also the exchange of energy between the different atmospheric layers, which might affect the terrestrial and marine environment, especially in the polar region.

EHPnet: The Earth Observing System

Vol. 113, No. 2 EnvironewsOpen AccessEHPnet: The Earth Observing System Erin E. Dooley Erin E. Dooley Search for more papers by this author Published:1 February 2005https://doi.org/10.1289/ehp.113-a93AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit In 1991, the National Aeronautics and Space Administration (NASA) embarked upon the extensive and comprehensive Earth Science Enterprise, a program to help us better understand what is happening on the Earth’s surface. The centerpiece of the Earth Science Enterprise is known as The Earth Observing System (EOS). The EOS website, located at http://eospso.gsfc.nasa.gov/, is designed to keep scientists, educators, and the news media informed about the system and its activities.EOS is composed of a series of satellites conducting long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and oceans. The first EOS satellite, Terra, was launched into orbit in December 1999. NASA hopes the data gathered by the system, the first to provide integrated measurements of processes occurring on Earth, can be used to help better predict climate change, oversee conservation efforts, and improve forecasting to help farmers, fishers, and other weather-dependent tradespeople.The For Scientists section of the website provides links to overviews of the field experiments that EOS conducts, and contains information on what sorts of measurements EOS takes and what types of instruments are used. Also within this section are links to brochures, reference books, data product catalogs, a bibliography of EOS-related publications, and a calendar of workshops and conference seminars conducted by EOS personnel.Teachers looking for EOS-related resources can visit the For Educators section. The EOS Education Project, with a link located under the Educational Links subhead, has been developed for teachers and students at all levels to teach about topics including geographic information systems and remote sensing. The project offers outreach programs for teachers and Internet-based classes. This section also features a directory of other EOS-related teaching materials, including brochures, fact sheets, posters, lithographs, and lesson plans that can be downloaded or ordered for free. Also available are online tools for calculating when a satellite will pass overhead and tracking various satellites’ current location in the sky. Links to other websites include the main NASA Earth Science Enterprise educational website and the homepages of related agencies such as the National Science Foundation.News writers have their own section on the website. Available under For News Media is the Earth Observatory Newsroom, which contains press releases on the latest EOS research, NASA news announcements, and a list of newly published research. This section also features the EOS Global Change Media Directory 2001. This resource lists 343 scientists working in fields such as ozone chemistry, global warming, and ecosystems who have expressed interest in working with the media. Science writers’ guides to individual spacecraft provide extensive background material and contact information.The site’s Data Services section provides links to the different types of data that the EOS and its partners provide. This section links to NASA’s Global Change Master Directory website, which provides extensive data sets on 13 topics, including agriculture, human dimensions, oceans, and sun–Earth interactions. Subscribers can add to the data sets and participate in an online discussion list.FiguresReferencesRelatedDetails Vol. 113, No. 2 February 2005Metrics About Article Metrics Publication History Originally published1 February 2005Published in print1 February 2005 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

Results of in-flight operation of scientific payload on micro-satellite Kolibri-2000

The realization of Russian–Australian scientific–educational micro-satellite Kolibri-2000 (weight of 20.5 kg), 20 March 2002, delivered into an orbit by “Progress M1-7”, was by the first item of the Program of Scientific–Educational Micro-Satellite (PSEMS’ 2002–2007) and designates a starting point of a series perspective scientific–educational micro-satellites (SEMS). In the Kolibri-2000 project, several schools equipped by School Center of Reception of the Information (SCRI), participate, including Russian schools (Obninsk) and two Australian schools in Sydney, Knox Grammar School and Ravenswood School for Girls. The results of the Kolibri-2000 first measurements on the orbit near International Space Station are presented in this paper which include the ionosphere reaction of April 2002 events. Our results address the understanding of the coupling and feedback in the Sun–Earth interaction in the space weather context.

Results of in-flight operation of scientific payload on micro-satellite “Kolibri-2000”

The realization of Russian–Australian scientific—educational micro-satellite “Kolibri-2000” (weight of 20.5 kg, http://www.kolibri2000.ru 20 March, 2002), delivered into an orbit by “Progress M1-7”, was the first item in the Program of Scientific—Educational Micro-Satellite (PSEMS' 2002–2007, http://iki.cosmos.ru/kollibri/mission1_e.htm) and designate the starting point of a series at perspective scientific—educational micro-satellites (SEMS, http://www.energia.ru/english/energia/sci-education/microsat/microsat-02.html). In the “Kolibri-2000” project, several schools equipped by School Center of Reception of the Information (SCRI), participated, including Russian schools (Obninsk http://ftschool.obninsk.org) and two Australian schools in Sydney, Knox Grammar School ( www.knox.nsw.edu.au) and Ravenswood School for Girls ( www.ravenswood.nsw.edu.au). The results of the “Kolibri-2000” first measurements on the orbit near the International Space Station will be submitted in this paper which include the ionosphere reaction during the April 2002 events, and address as understanding of the coupling and feedback in the Sun–Earth interaction.

Laboratory Antarctica: Research Contributions to Global Problems

Research in Antarctica is becoming increasingly important in the large interdisciplinary studies of connections within the earth's geosphere-biosphere system. Four examples of broad research areas are discussed. Upper atmosphere research explores the sun-earth interactions, which are most intense in the polar regions. The mass balance and dynamics of the large Antarctic ice sheet, and its paleoclimatic records recovered from deep ice cores, are important indicators of past and present global changes. Antarctica and sediment cores from the Southern Ocean contain the history of inception and growth of the ice masses and their subsequent fluctuations, and the long-term history of paleoclimate. The remarkable adaptations of Antarctic biota to extreme cold and drought may allow, through biotic monitoring, the detection of changes in the ocean and climate of Antarctica.

Exploration geophysics in Yugoslavia: the roots are deep

Among the worldwide geophysical community Yugoslavia is renowned for having produced several scientists who have made enormous contributions to modern geophysics. This is the appropriate opportunity to pay tribute to them. Rudjer Bošković (1711-1787) was born and educated in Dubrovnik, became a Fellow of the Royal Society (of London) and a professor in Paris and Milan. His contribution on sunspot phenomena (1922) is worthwhile reading for everyone interested in the geomagnetic field and related geophysics. Although his contributions in astronomy and geophysics are of the highest rank, Yugoslavia decided to name one of its nuclear research institutes (Zagreb) after him. Nikola Tesla (1856-1943) is far better known for his accomplishments in electrical engineering, especially in the field of electromagnetic phenomena, but every student of geophysics learns his name on first acquaintance with the earth's magnetic field. Milutin Milanković (1879-1958) formulated the mathematical basis of polar-wandering and continental drift, which exactly explained Alfred Wegener's descriptive hypothesis of the phenomenon. Although Milanković's theory of the insolation effect on the ice-age cycles (1941) is not of direct significance for exploration geophysics, it is important in geophysics for understanding one of the basic phenomena, that of the sunearth interaction. Andrija Mohorovičić (1857-1936) made a discovery of much closer relevance to the field of exploration geophysics, since we are prospecting within the earth's crust whose lower boundary is known as Mohorovičić's discontinuity. The earthquake on 8th October 1906, whose epicentre was 50 km southeast of Zagreb, the home city of Mohorovičić, was a challenge for him to study the phenomenon thoroughly. Mohorovičić's (1910) results were so fascinating that it took some time to appreciate them. It was many years later that the crust's lower boundary was recognised as Mohorovičić's discontinuity. Please note that it is neither the Moho nor the M-discontinuity: it is only correct to refer to it as Mohorovičić's discontinuity. Over a period of many years af ter 1906, the earth's crustal thickness was determined at isolated locations, but it was not determined systematically until the 1960s! The importance of the earth's crustal thickness was not appreciated until an understanding of palaeomagnetism, polar wandering, continental drift and plate tectonics became essential even for guiding the prospecting for mineral resources. During the 1960s the two Yugoslav geophysicists Milanković and Mohorovičić were among the most frequently quoted authors. At that time the two Yugoslav geophysical exploration companies (Geofizički Institut from Belgrade, and Geofizika from Zagreb) started systematic investigation of the earth's crustal thickness over Yugoslavia. The method applied was Deep Seismic Sounding (DSS), which is essentially seismic refraction. The thickness of the crust was determined along eight profiles generally oriented perpendicular to the Dinarides. According to Dragašević (1973) and Dragašević & Andrić (1974) the shotpoint-to-geophone distances were up to 600 km, and when joint refraction shooting was organised together with Soviet, Polish, Hungarian and Yugoslav geophysicists, the distances were as much as 1500 km with charges of up to 5000 kg. Some of the results of DSS are shown in Fig. 1 along a profile running from the Adriatic sea (the shotpoint at Petrovac) to the Danube (at Negotine, a city on the Yugoslav-Rumanian border). The DSS was technically a demanding challenge for Yugoslav geophysicists, but the results were rewarding.