Sibeck D.G.,NASA |
Angelopoulos V.,University of California at Los Angeles |
Brain D.A.,University of California at Berkeley |
Delory G.T.,University of California at Berkeley |
And 17 more authors.
Space Science Reviews | Year: 2011
NASA's two spacecraft ARTEMIS mission will address both heliospheric and planetary research questions, first while in orbit about the Earth with the Moon and subsequently while in orbit about the Moon. Heliospheric topics include the structure of the Earth's magnetotail; reconnection, particle acceleration, and turbulence in the Earth's magnetosphere, at the bow shock, and in the solar wind; and the formation and structure of the lunar wake. Planetary topics include the lunar exosphere and its relationship to the composition of the lunar surface, the effects of electric fields on dust in the exosphere, internal structure of the Moon, and the lunar crustal magnetic field. This paper describes the expected contributions of ARTEMIS to these baseline scientific objectives. © 2011 US Government.
Shay M.A.,University of Delaware |
Phan T.D.,University of California at Berkeley |
Haggerty C.C.,University of Delaware |
Fujimoto M.,ISAS |
And 4 more authors.
Geophysical Research Letters | Year: 2016
Kinetic particle-in-cell simulations are used to identify signatures of the electron diffusion region (EDR) and its surroundings during asymmetric magnetic reconnection. A "shoulder" in the sunward pointing normal electric field (EN > 0) at the reconnection magnetic field reversal is a good indicator of the EDR and is caused by magnetosheath electron meandering orbits in the vicinity of the X line. Earthward of the X line, electrons accelerated by EN form strong currents and crescent-shaped distribution functions in the plane perpendicular to B. Just downstream of the X line, parallel electric fields create field-aligned crescent electron distribution functions. In the immediate upstream magnetosheath, magnetic field strength, plasma density, and perpendicular electron temperatures are lower than the asymptotic state. In the magnetosphere inflow region, magnetosheath ions intrude resulting in an Earthward pointing electric field and parallel heating of magnetospheric particles. Many of the above properties persist with a guide field of at least unity. © 2016. American Geophysical Union. All Rights Reserved.
Morita Y.,Japan Aerospace Exploration Agency |
Hori K.,Space Transportation Engineering |
Imoto T.,Japan Aerospace Exploration Agency |
Ohtsuka H.,IHI Corporation |
And 2 more authors.
Advances in the Astronautical Sciences | Year: 2010
What should we evolve the solid rocket launchers in the near future? The JAXA is developing the Advanced Solid Rocket (ASR), or recently nicknamed Epsilon rocket, as a successor to the M-V launch vehicle, the world best performance solid rocket system that can be utilized even for planetary missions. Epsilon rocket is a result of next generation technologies including a highly intelligent autonomous check-out system and a mobile launch control, which is connected to not only the solid rocket but also future space transportation systems. It aims at improving the efficiency and the cost performance of the launch system. Far beyond this effort, the attention should be directed toward a revolution of the manufacture. The Low melting temperature Thermoplastic Propellant (LTP), now at the experimental stage, is expected to convert a large-scale and inefficient manufacture process to one of a small-scale and high utilization frequency, resulting in a significant cost reduction. This paper reveals the direction toward evolution of the next generation solid-propellant rockets: simplification of the launch system and the manufacture process.
On 12 January 2016, the Japan Aerospace Exploration Agency (JAXA) presented their ASTRO-H satellite to the media at the Tanegashima Space Center, situated on a small island in the south of Japan. The satellite, developed with institutions in Japan, the US, Canada and Europe, is now ready to be mounted on an H-IIA rocket for launch on 12 February. ASTRO-H is a new-generation satellite, designed to study some of the most powerful phenomena in the Universe by probing the sky in the X-ray and gamma-ray portions of the electromagnetic spectrum. Scientists will investigate extreme cosmic environments ranging from supernova explosions to supermassive black holes at the centres of distant galaxies, and the hot plasma permeating huge clusters of galaxies. ESA contributed to ASTRO-H by partly funding various elements of the four science instruments, by providing three European scientists to serve as science advisors and by contributing one scientist to the team in Japan. In return for ESA's contribution, European scientists will have access to the mission's data. Traditionally, Japan's astronomy satellites receive a provisional name consisting of the word 'ASTRO' followed by a letter of the latin alphabet – in this case H, because it is the eighth project in JAXA's astronomical series. JAXA will announce the new name after launch. ASTRO-H is a new-generation satellite for high-energy astrophysics, developed by the Japan Aerospace Exploration Agency (JAXA) in collaboration with institutions in Japan, the US, Canada, and Europe. Its four instruments span the energy range 0.3-600 keV, including soft X-rays, hard X-rays and soft gamma rays. ESA's contribution consists in funding the procurement of a number of items on the various instruments, three European scientists who will serve as advisors to the mission's core science programme, and one full-time scientist based at the Institute of Space and Astronautical Science (ISAS), Japan, to support in-flight calibration, science software testing and data analysis. Support to European users will be provided by scientists at ESA's European Space Astronomy Centre in Madrid, Spain, and at the European Science Support Centre at the ISDC Data Centre for Astrophysics, University of Geneva, Switzerland. Explore further: Japan launches satellite for better GPS coverage (Update)
Phan T.D.,University of California at Berkeley |
Paschmann G.,Max Planck Institute for Extraterrestrial Physics |
Gosling J.T.,University of Colorado at Boulder |
Oieroset M.,University of California at Berkeley |
And 3 more authors.
Geophysical Research Letters | Year: 2013
We have performed a statistical study of THEMIS spacecraft crossings of the asymmetric dayside magnetopause to test the prediction that the diamagnetic drift of the X-line due to a plasma pressure gradient across the magnetopause can suppress magnetic reconnection. The study includes crossings both when reconnection exhausts were present and when they were absent in the current sheet. When we restrict the survey to the subsolar region (10 < MLT < 14), we find that for low Δβ (the difference of plasma β on the two sides of the current sheet) the majority of reconnection events occurred over a large range of magnetic shears, whereas when Δβ was high reconnection events occurred only for high shears. Furthermore, nonreconnection events occurred primarily in the Δβ-shear regime in which reconnection is predicted to be suppressed, in good agreement with theory. The Δβ-shear condition should have general consequences for the occurrence of reconnection in space and laboratory plasmas. © 2013. American Geophysical Union. All Rights Reserved.