Search Publications
Comparisons between ion distributions retrieved from ENA images of the ring current and contemporaneous, multipoint ion measurements recorded in situ during the major magnetic storm of 15 May 2005
Barabash, S.; Liu, Z. X.; Brandt, P. C. +5 more
The Neutral Atom Detector Unit (NUADU) aboard the TC-2 spacecraft recorded energetic neutral atom (ENA) image data for >3 h during part of the main and recovery phases of a major magnetic storm on 15 May 2005. A custom designed, constrained linear inversion method was applied to retrieve ring current ion distributions in the ENA records out to …
Spectroscopic Studies of Limb Spicules. I Radial and Turbulent Velocities
Shoji, Makiko; Nishikawa, Takara; Kitai, Reizaburo +1 more
We made high-resolution spectroscopic observations of limb spicules in Hα using the Vertical Spectrograph of Domeless Solar Telescope at Hida Observatory. While more than half of the observed spicules have Gaussian line-profiles, some spicules have distinctly asymmetric profiles, which can be fitted to two Gaussian components. The faster component…
On the correlation between Broad-Band ELF wave power and ion fluxes in the cusp
Jacobsen, K. S.; Moen, J. I.
We present a study of Broad-Band Extremely Low Frequency (BB-ELF) electric fields in the mid-altitude (4-6 Earth radii) cusp during periods of southward interplanetary magnetic field, using data from the Cluster spacecraft. Magnetospheric boundary layers are identified and classified according to particle precipitation characteristics. We find tha…
On the modeling of planetary plasma environments by a fully kinetic electromagnetic global model HYB-em
Kallio, E.; Pohjola, V.
We have developed a fully kinetic electromagnetic model to study instabilities and waves in planetary plasma environments. In the particle-in-a-cell (PIC) model both ions and electrons are modeled as particles. An important feature of the developed global kinetic model, called HYB-em, compared to other electromagnetic codes is that it is built up …
TYC 2675-663-1: a newly discovered W UMa system in an active state
Montesinos, B.; Ribas, I.; Mas-Hesse, J. M. +4 more
Aims: The recently discovered eclipsing binary system TYC 2675-663-1 is an X-ray source and shows properties in the optical that are similar to the W UMa systems, but are somewhat unusual compared to what is seen in other contact binary systems. The goal of this work is to characterize its properties and investigate its nature by means of det…
Center to limb variation of penumbral Stokes V profiles
Franz, M.; Schlichenmaier, R.
We investigated the horizontal and the vertical component of the Evershed flow (EF). To this end, we computed average Stokes V profiles for various velocity classes in penumbrae at different heliocentric angles. Our results show that for blueshifted profiles an additional lobe with the same polarity as the spot is present in the blue side of the a…
Intensity Distribution and Contrast of the Solar EUV Network
Raju, K. P.
Intensity distributions of the EUV network and the cell interior in the solar atmosphere have been obtained in fourteen emission lines from Solar and Heliospheric Observatory (SOHO)/Coronal Diagnostic Spectrometer (CDS) observations. The formation temperature of the observed lines is in the range log T=4.90 - 6.06 (T in Kelvin), and hence they rep…
Spectrophotometric variability of the magnetic CP star 56 Arietis in spectral region from 1950 to 3200 Å
Sokolov, Nikolay A.
The spectrophotometric variability of the magnetic CP star 56 Arietis (56 Ari) in the ultraviolet spectral region from 1950 to 3200 Å is investigated. This study is based on the archival International Ultraviolet Explorer data obtained at different phases of the rotational cycle. The brightness of 56 Ari is not constant in the investigated wavelen…
India’s first lunar mission Chandrayaan-1 initial phase orbit determination
Vighnesam, N. V.; Sonney, Anatta; Gopinath, N. S.
India's first Moon mission Chandrayaan-1 carrying eleven scientific instruments for the purpose of expanding scientific knowledge about the Moon was launched on 22 October 2008. The spacecraft was put into Moon's polar, circular orbit of about (100×100) km on 12 November 2008 by carrying out a sequence of Earth bound and Lunar bound maneuvers. Pre…
Absolute parameters of the newly-identified contact binary star IS Canis Major
Özkardeş, B.; Erdem, A.
This paper presents the results of the first high-resolution spectroscopic observations of the Southern W UMa type system IS CMa. Spectroscopic observations of the system were made at Mt. John University Observatory using a HERCULES fibre-fed échelle spectrograph in September 2007. The first radial velocities of the component stars of the system w…