Tracing the magnetic topology of coronal mass ejection events by Ulysses/HI-SCALE energetic particle observations in and out of the ecliptic

In January 2000, the Ulysses spacecraft observed an ICME event at 43° S heliographic latitude and ∼ 4.1 AU. We use electron (E _e>38 keV) observations to trace the topology of the IMF embedded within the ICME. The still controversial issue of whether ICMEs have been detached from the solar corona or are still magnetically anchored to it when they arrive at the spacecraft is tackled. An in ecliptic ICME event is also presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Solar Fine-Scale Structures. I. Spicules and Other Small-Scale, Jet-Like Events at the Chromospheric Level: Observations and Physical Parameters

Over the last two decades the uninterrupted, high resolution observations of the Sun, from the excellent range of telescopes aboard many spacecraft complemented with observations from sophisticated ground-based telescopes have opened up a new world producing significantly more complete information on the physical conditions of the solar atmosphere than before. The interface between the lower solar atmosphere where energy is generated by subsurface convection and the corona comprises the chromosphere, which is dominated by jet-like, dynamic structures, called mottles when found in quiet regions, fibrils when found in active regions and spicules when observed at the solar limb. Recently, space observations with Hinode have led to the suggestion that there should exist two different types of spicules called Type?I and Type?II which have different properties. Ground-based observations in the Ca?ii H and K filtergrams reveal the existence of long, thin emission features called straws in observations close to the limb, and a class of short-lived events called rapid blue-shifted excursions characterized by large Doppler shifts that appear only in the blue wing of the Ca?ii infrared line. It has been suggested that the key to understanding how the solar plasma is accelerated and heated may well be found in the studies of these jet-like, dynamic events. However, while these structures are observed and studied for more than 130 years in the visible, but also in the UV and EUV emission lines and continua, there are still many questions to be answered. Thus, despite their importance and a multitude of observations performed and theoretical models proposed, questions regarding their origin, how they are formed, their physical parameters, their association with the underlying photospheric magnetic field, how they appear in the different spectral lines, and the interrelationship between structures observed in quiet and active regions on the disk and at the limb, as well as their role in global processes has not yet received definitive answers. In addition, how they affect the coronal heating and solar wind need to be further explored. In this review we present observations and physical properties of small-scale jet-like chromospheric events observed in active and quiet regions, on the disk and at the limb and discuss their interrelationship.     

Dynamical fine structures of the chromosphere

We have studied the spatial structure and temporal evolution of a chromospheric region with chains of mottles at the junction of three supergranules. The observations were obtained with the Multichannel Subtractive Double Pass spectrograph operating in H at the Pic du Midi Observatory. From a statistical point of view the fine structures were stable in intensity over the observation period (15 min), while the line of sight velocity showed remarkable changes within a few minutes. A detailed analysis shows that the predominant pattern of bulk motion in the dark mottles is that of downflow at their footpoints and upflow at their tops, which is followed by downflows along the whole structure and that this process repeats itself several times during their lifetime.