The twin STEREO spacecraft were launched on October 26, 2006, at 00:52 UT from Kennedy Space Center aboard a Delta 7925 launch vehicle. After a series of highly eccentric Earth orbits with apogees beyond the moon, each spacecraft used close flybys of the moon to escape into orbits about the Sun near 1 AU. Once in heliospheric orbit, one spacecraft trails Earth while the other leads. As viewed from the Sun, the two spacecraft separate at approximately 44 to 45 degrees per year. The purposes of the STEREO Mission are to understand the causes and mechanisms of coronal mass ejection (CME) initiation and to follow the propagation of CMEs through the inner heliosphere to Earth. Researchers will use STEREO measurements to study the mechanisms and sites of energetic particle acceleration and to develop three-dimensional (3-D) time-dependent models of the magnetic topology, temperature, density and velocity of the solar wind between the Sun and Earth. To accomplish these goals, each STEREO spacecraft is equipped with an almost identical set of optical, radio and in situ particles and fields instruments provided by U.S. and European investigators. The SECCHI suite of instruments includes two white light coronagraphs, an extreme ultraviolet imager and two heliospheric white light imagers which track CMEs out to 1 AU. The IMPACT suite of instruments measures in situ solar wind electrons, energetic electrons, protons and heavier ions. IMPACT also includes a magnetometer to measure the in situ magnetic field strength and direction. The PLASTIC instrument measures the composition of heavy ions in the ambient plasma as well as protons and alpha particles. The S/WAVES instrument uses radio waves to track the location of CME-driven shocks and the 3-D topology of open field lines along which flow particles produced by solar flares. Each of the four instrument packages produce a small real-time stream of selected data for purposes of predicting space weather events at Earth. NOAA forecasters at the Space Environment Center and others will use these data in their space weather forecasting and their resultant products will be widely used throughout the world. In addition to the four instrument teams, there is substantial participation by modeling and theory oriented teams. All STEREO data are freely available through individual Web sites at the four Principal Investigator institutions as well as at the STEREO Science Center located at NASA Goddard Space Flight Center.

The STEREO Mission: An Introduction

Astronomical data analysis software and systems

Data Reduction And Error Analysis For The Physical Sciences

Achieving optical gain and/or lasing in silicon has been one of the most challenging goals in silicon-based photonics because bulk silicon is an indirect bandgap semiconductor and therefore has a very low light emission efficiency. Recently, stimulated Raman scattering has been used to demonstrate light amplification and lasing in silicon. However, because of the nonlinear optical loss associated with two-photon absorption (TPA)-induced free carrier absorption (FCA), until now lasing has been limited to pulsed operation. Here we demonstrate a continuous-wave silicon Raman laser. Specifically, we show that TPA-induced FCA in silicon can be significantly reduced by introducing a reverse-biased p-i-n diode embedded in a silicon waveguide. The laser cavity is formed by coating the facets of the silicon waveguide with multilayer dielectric films. We have demonstrated stable single mode laser output with side-mode suppression of over 55 dB and linewidth of less than 80 MHz. The lasing threshold depends on the p-i-n reverse bias voltage and the laser wavelength can be tuned by adjusting the wavelength of the pump laser. The demonstration of a continuous-wave silicon laser represents a significant milestone for silicon-based optoelectronic devices.

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A continuous-wave Raman silicon laser

We must all accept that science is data and that data are science, and thus provide for, and justify the need for the support of, much-improved data curation. (Hanson, Sugden, & Alberts) 
 
Researchers are producing an unprecedented deluge of data by using new methods and instrumentation. Others may wish to mine these data for new discoveries and innovations. However, research data are not readily available as sharing is common in only a few fields such as astronomy and genomics. Data sharing practices in other fields vary widely. Moreover, research data take many forms, are handled in many ways, using many approaches, and often are difficult to interpret once removed from their initial context. Data sharing is thus a conundrum. Four rationales for sharing data are examined, drawing examples from the sciences, social sciences, and humanities: (1) to reproduce or to verify research, (2) to make results of publicly funded research available to the public, (3) to enable others to ask new questions of extant data, and (4) to advance the state of research and innovation. These rationales differ by the arguments for sharing, by beneficiaries, and by the motivations and incentives of the many stakeholders involved. The challenges are to understand which data might be shared, by whom, with whom, under what conditions, why, and to what effects. Answers will inform data policy and practice. © 2012 Wiley Periodicals, Inc.

科研数据共享的挑战 (The Conundrum of Sharing Research Data)

On 1 July 2004, the Cassini spacecraft performed its Saturn orbit insertion (SOI), twice crossing the equatorial plane at ∼2.6Rs (from Saturn’s spin axis) between the G and F rings. The HF radio receiver (HFR-RPWS) observed a peak at the upper-hybrid frequency fuh and weak but steady banded emissions above the gyrofrequency, having well-defined minima at gyroharmonics. It was “déjà vu” with respect to the Earth and Jupiter magnetospheres with spacecraft using similar instrumentation. Since SOI, we have observed such features around most of the Cassini perikrones (periapses at Saturn), sometimes including emissions between the gyroharmonic bands above fuh. We interpret these noise bands between gyroharmonics as quasi-thermal noise in Bernstein modes, which are electrostatic waves propagating almost perpendicularly to the magnetic field. The weak steady emissions between the gyroharmonics are mainly sustained by the suprathermal electron population and may be enhanced above fuh by specific resonances of Bernstein modes – the so called fQ frequencies. Their observation depends on the antenna shape and length compared to the basic plasma scales and requires a receiver with adequate sensitivity. On Cassini, we show that they can be detected below fuh whenever the local electron gyroradius is shorter than ∼9m.

Quasi Thermal Noise in Bernstein Waves at Saturn

Planetary radio emissions as space weather remote probes

We investigate the beaming of 11 Io‐Jupiter decametric (Io‐DAM) emissions observed by Juno/Waves, the Nançay Decameter Array, and NenuFAR. Using an up‐to‐date magnetic field model and three methods to position the active Io Flux Tube (IFT), we accurately locate the radiosources and determine their emission angle θ from the local magnetic field vector. These methods use (a) updated models of the IFT equatorial lead angle, (b) ultraviolet (UV) images of Jupiter's aurorae, and (c) multi‐point radio measurements. The kinetic energy Ee− of source electrons is then inferred from θ in the framework of the Cyclotron Maser Instability. The precise position of the active IFT achieved from methods (b and c) can be used to test the effective plasma density of the Io torus. Simultaneous radio/UV observations reveal that multiple Io‐DAM arcs are associated with multiple UV spots and provide the first direct evidence of an Io‐DAM arc associated with a trans‐hemispheric beam UV spot. Multi‐point radio observations probe the Io‐DAM sources at various altitudes, times and hemispheres. Overall, θ varies a function of frequency (altitude), by decreasing from 75°−80° to 70°−75° over 10−40 MHz with slightly larger values in the northern hemisphere, and independently varies as a function of time (or longitude of Io). Its uncertainty of a few degrees is dominated by the error on the longitude of the active IFT. The inferred values of Ee− also vary as a function of altitude and time. For the 11 investigated cases, they range from 3 to 16 keV, with a 6.6 ± 2.7 keV average.

Determining the Beaming of Io Decametric Emissions: A Remote Diagnostic to Probe the Io‐Jupiter Interaction

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Analysis of Jovian low-frequency radio emissions based on stereoscopic observations with Juno and Earth-based radio telescopes

In EuroPlaNet-RI, JRA4 must prepare essential tools allowing the planetary science community to interrogate some selected data centres, access and process data and visualize the results. The first requirement for enabling access to different data centres is to use a standard protocol. This protocol, PDAP (Planetary Data Access Protocol) has been defined by the IPDA to enable standard access to PDS and PSA data archives. In this paper , we present a prototype service that enables access to planetary data from several data providers, different from PSA and PDS, using the PDAP protocol. The specific mission of the IPDA (International Planetary Data Alliance) is to facilitate global access and exchange of high quality scientific data products across international boundaries. The data standards within the IPDA, including data models and dictionaries are based on the NASA Planetary Data System (PDS) that is the de-facto standard for all planetary data. The main existing outcome of IPDA is PDAP (Planetary Data Access Protocol) to access datasets, products and images. The PDAP protocol has been designed close to SIAP protocol from IVOA, but with planetary data in mind: • PDS

Baptiste Cecconi

Papers

Quasi Thermal Noise in Bernstein Waves at Saturn

Planetary radio emissions as space weather remote probes

Determining the Beaming of Io Decametric Emissions: A Remote Diagnostic to Probe the Io‐Jupiter Interaction

Analysis of Jovian low-frequency radio emissions based on stereoscopic observations with Juno and Earth-based radio telescopes

A prototype service to access planetary data using the IPDA/PDAP protocol