Search Publications
Wave vector analysis methods using multi-point measurements
Glassmeier, K. -H.; Narita, Y.; Motschmann, U.
Recent developments of multi-point measurements in space provide a means to analyze spacecraft data directly in the wave vector domain. For turbulence study this means that we are able to estimate energy, helicity, and higher order moments in the wave vector domain without assuming Taylor's hypothesis or axisymmetry around the mean magnetic field.…
Magnetic tension of sunspot fine structures
Tiwari, Sanjiv Kumar; Venkatakrishnan, P.
Context. The equilibrium structure of sunspots depends critically on its magnetic topology and is dominated by magnetic forces. Tension force is one component of the Lorentz force, which balances the gradient of magnetic pressure in force-free configurations.
Aims: We employ the tension term of the Lorentz force to clarify the structure of su…
X-ray observations of classical novae: Theoretical implications
Hernanz, M.; Sala, G.
Detection of X-rays from classical novae, both in outburst and post-outburst, provides unique and crucial information about the explosion mechanism. Soft X-rays reveal the hot white dwarf photosphere, whenever hydrogen (H) nuclear burning is still on and expanding envelope is transparent enough, whereas harder X-rays give information about the eje…
Machine Leaning-Based Investigation of the Associations between CMEs and Filaments
Ipson, S.; Colak, T.; Qahwaji, R. +1 more
In this work we study the association between eruptive filaments/prominences and coronal mass ejections (CMEs) using machine learning-based algorithms that analyse the solar data available between January 1996 and December 2001. The support vector machine (SVM) learning algorithm is used for the purpose of knowledge extraction from the association…
Comparison of energies between eruptive phenomena and magnetic field in AR 10930
Ravindra, B.; Howard, Timothy A.
We present a study comparing the energy carried away by a coronal mass ejection (CME) and the radiative energy loss in associated flare plasma, with the decrease in magnetic free energy during a release in active region NOAA 10930 on December 13, 2006 during the declining phase of the solar cycle 23. The ejected CME was fast and directed towards t…
Hydrogen Permitted Lines in the First Near-IR Spectra of Th 28 Microjet: Accretion or Ejection Tracers?
Nisini, Brunella; Bacciotti, Francesca; Coffey, Deirdre +1 more
We report the first near-infrared detection of the bipolar microjet from T Tauri star ThA 15-28 (hereafter Th 28). Spectra were obtained with Very Large Telescope (VLT)/ISAAC for the slit both perpendicular and parallel to the flow to examine jet kinematics and gas physics within the first arcsecond from the star. The jet was successfully detected…
Observations of the Optical Transient in NGC 300 with AKARI/IRC: Possibilities of Asymmetric Dust Formation
Tanaka, M.; Matsuhara, H.; Nakagawa, T. +10 more
We present the results of near-infrared (NIR) multi-epoch observations of the optical transient in the nearby galaxy NGC 300 (NGC 300-OT) at 398 and 582 days after the discovery with the Infrared Camera (IRC) on board AKARI. NIR spectra (2-5 µm) of NGC 300-OT were obtained for the first time. They show no prominent emission nor absorption fe…
Optical depth and its scale-height in Valles Marineris from HRSC stereo images
Keller, H. U.; Grieger, B.; Hoekzema, N. M. +4 more
We measured the optical depth of the Martian atmosphere as a function of altitude above two opposing scree walls of the Valles Marineris, from stereo images that were taken with the High Resolution Stereo Camera (HRSC) of Mars Express on June 3, 2004, during orbit 471. The optical depths were measured from contrast differences between the stereo i…
Suzaku Observation of Strong Fluorescent Iron Line Emission from the Young Stellar Object V1647 ORI During its New X-ray Outburst
Hamaguchi, Kenji; Kastner, Joel H.; Richmond, Michael +2 more
The Suzaku X-ray satellite observed the young stellar object (YSO) V1647 Ori on 2008 October 8 during the new mass accretion outburst reported in 2008 August. During the 87 ks observation with a net exposure of 40 ks, V1647 Ori showed a high level of X-ray emission with a gradual decrease in flux by a factor of 5 and then displayed an abrupt flux …
The EFW Data in the CAA
André, M.; Khotyaintsev, Y.; Eriksson, A. +1 more
The Electric Field and Waves (EFW) instrument measures the 2D electric field (in the spacecraft spin plane) and spacecraft potential with sampling rates, on some occasions, up to 36,000 samples/s. We present a summary of the CAA data products produced from the EFW measurements. We briefly describe the production pipeline from the raw data to final…