Search Publications
Quasi-Thermal Noise Diagnostics in Space Plasmas
Issautier, K.; Moncuquet, M.; Meyer-Vernet, N. +2 more
We present the method of plasma diagnostics by quasi-thermal noise spectroscopy and show examples of application in the solar wind and the Earth's plasmasphere. Using only an electric antenna and a radio receiver, diagnostics of various space environments (magnetized or not) can be obtained in situ. Because of its accuracy, this technique can be u…
The heliosphere after Ulysses
Marsden, R. G.
Launched in October 1990, the ESA-NASA Ulysses mission has conducted the very first survey of the heliosphere within 5 AU of the Sun over the full range of heliolatitudes. With polar passes taking place in 1994 and 1995, the timing of the mission has enabled Ulysses to characterise the global structure of the heliosphere at solar minimum, when the…
Acceleration and Transport of Energetic Charged Particles in Space
Jokipii, J. R.
Energetic charged particles or cosmic rays are found in space wherever the ambient matter density is small enough to allow them to exist. Their observed kinetic energies vary from just above the local thermal energies to in excess of 1020 eV. The energy spectrum is quite smooth, suggesting that a common mechanism is responsible for part…
HST/NICMOS Observations of M82
Rieke, George H.; Alonso-Herrero, Almudena; Rieke, Marcia J. +1 more
The irregular galaxy M82 is known as the archetypal starburst galaxy. Its proximity (3.5 Mpc) makes this galaxy an ideal laboratory for studying the properties of its starburst. The detailed morphology of the [FeII] 1.644 µm and emission Paα (at 1.87 µm) is revealed by the NICMOS images. The peak of the 2.2 µm continuu…
Electron Temperature in the Solar Wind From a Kinetic Collisionless Model: Application to High-Latitude Ulysses Observations
Issautier, Karine; Meyer-Vernet, Nicole; Pierrard, Viviane +1 more
We use a kinetic collisionless model of the solar wind to calculate the radial variation of the electron temperature and obtain analytical expressions at large radial distances. In order to be compared with Ulysses observations, the model, which initially assumed a radial magnetic field, has been generalized to a spiral magnetic field. We present …
The Fossil Starburst in M82
O'Connell, Robert W.; Gallagher, John S., III; De Grijs, Richard
We present high-resolution optical and near-infrared HST observations of two adjacent regions in the fossil starburst region inM82, M82 B1 and B2. The presence of both the active and the fossil starburst in M82 provides a unique physical environment to study the stellar and dynamical evolution of star cluster systems. The cluster population in B2 …
The Mid-Infrared View of Star Formation in Collisional Ring Galaxies
Cesarsky, C.; Sauvage, M.; Vigroux, L. +4 more
We present mid-infrared images and spectra of Arp 10 and Arp 118, two collisional ring galaxies observed as part of the ISOCAM GT program CAMACTIV (P.I.: I.F. Mirabel). The observations reveal the distribution of hot dust in the galaxies and enable us to probe the mechanisms responsible for the heating of the ISM. Unlike the peculiar mid-infrared …
Magnetic Field Line Transport in the Heliosphere and Energetic Particle Propagation from Corotating Interaction Regions to High Heliographic Latitudes
Zimbardo, Gaetano; Veltri, Pierluigi; Pommois, Pierre
A numerical model of magnetic turbulence allows us to compute the diffusion coefficients for different degrees of anisotropy, and in particular for the cases corresponding to the solar wind. We consider here the problem of the propagation of the energetic particles accelerated by corotating interaction regions (CIRs) and observed by Ulysses at hig…
Quasi-thermal Noise Spectra Measured by a Dipole Antenna in the Upper Hybrid frequency band
Chugunov, Yury V.; Kazarova, Anna Yu.; Mareev, Eugene A. +3 more
Quasi-thermal noise (QTN) spectroscopy is one of the most effective tools for in situ diagnostics in space plasmas (Meyer-Vernet et al., 1998; Meyer-Vernet and Perche, 1989; Chugunov and Trakhtengerts, 1978). This method produces routine measurements of the bulk electron density and temperature; recently it has been extended to measure the ion bul…
On the Magnetic Energy Avalanche in the Solar Atmosphere
Tarbell, T. D.; Ryutova, M. P.
We discuss a mechanism of energy production associated with the acoustic and MHD shocks produced by colliding and reconnecting flux tubes and present the observational results showing a connection between the dynamic changes in the photosphere and the high velocity and heating events in the transition region. We suggest that these processes may pr…