List of Figures

Watch/download Movie Figure 1: (mpg-Movie; 16433 KB)
Movie: A sequence of images taken with EIT on SOHO in the light of the 19.5 nm line, between October 27 and November 7, 2003. Several active regions associated with big sunspots released a series of major flares and CMEs: the “Halloween events”. The “snowstorms” following the major eruptions were caused by relativistic protons from the flare, that reached the Earth within minutes and were able to penetrate the spacecraft and instrument housings.
Watch/download Movie Figure 2: (mpg-Movie; 13287 KB)
Movie: A sequence of white-light images taken with the coronagraph LASCO C2 on SOHO, between October 27 and 31, 2003. Several halo CMEs occurred, but they are hard to recognize because of the violent “snowstorms” from relativistic SEPs. Note the little Kreutz comet plunging into the Sun on October 28, just hours before the first major eruption.
Watch/download Movie Figure 3: (mpg-Movie; 21695 KB)
Movie: A similar sequence, taken with the coronagraph LASCO C3 on SOHO, between October 18 and November 2003.
View Image Figure 4:
The Halloween series (from October 28 to November 6, 2003) of X-ray flares (upper 2 panels), interplanetary magnetic field (inserted panel; the red curve is the Bz component), SEP fluxes (next 3 panels), and geomagnetic index (Kp) variations (bottom panel). The data were assembled from the NOAA webpages starting from External Linkhttp://www.sec.noaa.gov/today.html and the ACE page at External Linkhttp://sec.noaa.gov/ace/ACErtsw_home.html.
View Image Figure 5:
Eclipse image of August 11, 1999, combined with a simultaneously taken coronagraph image (LASCO C2 on SOHO). For both images, the contrast was artificially enhanced in order to reveal the large-scale coronal structures and their sources in the lower corona (color print courtesy of S. Koutchmy, description in Koutchmy et al., 2004).
Watch/download Movie Figure 6: (mpg-Movie; 12197 KB)
Movie: A sequence of white-light images taken with the coronagraph LASCO C3 on SOHO, between December 22 and 28, 1996. The Sun is at its minimum of activity. The density fluctuations in the slow solar wind near the equatorial plane makes this type of solar wind visible. Note the passage of the (occulted) Sun through the milky way around Christmas time. Note further the little Kreutz comet plunging into the Sun on December 22.
View Image Figure 7:
This figure shows the two states by their different brightness in the corona. Note also how well separated from each other they are, both in the low corona as well as in the extended corona, i.e., in the solar wind.
View Image Figure 8:
The “ballerina model” of the 3-D heliosphere, according to Alfvén (1977).
View Image Figure 9:
A coronagraph view of the extended minimum corona on February 1, 1996. It is composed from an image taken by the LASCO C1 coronagraph onboard SOHO in the light of the green coronal emission line at 530.3 nm (inner part) and a white-light image taken by the LASCO C2 coronagraph (outer part). From Schwenn et al. (1997).
View Image Figure 10:
An idealized view of a corotating interaction region (CIR) and its evolution from a rectangular speed profile at the Sun into a more gradual speed increase at 1 AU. From Schwenn (1990).
View Image Figure 11:
The “high-intensity long-duration continuous AE activity (HILDCAA) event” of May 23 to 28, 1979, and the related Alfvén wave train within the high-speed solar wind stream. The excursions of the geomagnetic AE-index follow the Bz excursions in very much detail, with a time delay of about 100 minutes. Note that within the compression region in front of the stream the Bz component is also negative, and AE reacts similarly. The global Dst index is not affected. From Tsurutani and Gonzalez (1987).
View Image Figure 12:
A 27-day Bartels display of IMF polarity, coronal hole occurrence (plus 3 days to allow for Sun–Earth transit time), solar wind speed at Earth, and geomagnetic disturbance index C9. A 27-day average sunspot number is indicated in the narrow strip on the extreme right. Coronal holes were counted only when they occurred within 400 of the solar equator. The color coding was chosen such that commonalities are best visible (for details see Sheeley Jr and Harvey, 1981).
Watch/download Movie Figure 13: (mpg-Movie; 312 KB)
Movie: The flare on June 7, 2000, 1526 – 1621 UT, as seen by the H-alpha telescope (HASTA) in El Leoncito, Argentina External Linkhttp://www.oafa.fcefn.unsj-cuim.edu.ar/hasta/.
View Image Figure 14:
RHESSI Gamma-ray count spectrum from 0.3 to 10 MeV, integrated over the interval 0027:20 – 0043:20 UT. The lines show the different components of the model used to fit the spectrum. From Lin et al. (2003).
View Image Figure 15:
A representative radial profile of the electron plasma frequency in the solar wind illustrating the generation of electron plasma oscillations and the subsequent electromagnetic radiation at the plasmafrequency and its harmonic. From Gurnett et al. (1980).
View Image Figure 16:
Signal amplitude for a number of radio wave channels during the type III radio burst on December 7, 1977, as observed from Helios 2. From Kellogg (1980).
View Image Figure 17:
Example of a flare hard X-ray burst observed by RHESSI with corresponding solar type III radio burst and energetic electrons (and Langmuir waves) observed in situ by the WIND spacecraft (Krucker and Lin, 2002). Top panel: GOES soft X-rays; second panel: Spectrogram of RHESSI X-rays from 3 to 250 keV; third and fourth panels: radio emission observed by the WIND WAVES instrument; fifth panel: Electrons from 20 to 400 keV observed by WIND 3-DP instrument. From Lin (2005).
View Image Figure 18:
The radio type II burst of November 1, 2003, from 22:00 UT on. This is a clear example of a strong metric type II burst that extends from 300 to 10 MHz. It was observed from 3 independent instruments: from the WAVES instrument on the WIND spacecraft and the ground-based helio-spectrogtraphs. The WAVES data cover the frequency range below 14 MHz, the BIRS data run from 14 to 57 MHz, and the Culgoora data run from 57 to 570 MHz. Fundamental and harmonic bands of the type II are easily seen, along with splitting of each band. After the type II bands, some broadband type IV is seen in the Culgoora and BIRS data. A short, type II like feature is seen in the BIRS data between 23:06 and 23:14 UT. The light area in the BIRS data between 22:34 and 22:48 UT results from ionospheric absorption of the galactic background due to solar UV. From Cane and Erickson (2005).
View Image Figure 19:
Dynamic radio spectrum (A) of the solar type II burst during the event on June 30, 1995. The “backbone” is slowly drifting from 60 to 42 MHz. The “herringbones” are nicely visible during the whole event. The radio intensity is coded by grey scale. The bottom frames (B, C) present the intensity time derivative of the individual “herringbones.” From Mann and Klassen (2005).
View Image Figure 20:
Dynamic spectra of the WIND-WAVES radio data from January 6 to 11, 1997 in the frequency range from 23 to 245 kHz. The ordinate scale is the inverse of the observing frequency. The observed type II radio emissions for this event are bracketed by the upper two lines that originate from the CME lift-off time at 15:00 UT on January 6. For a more detailed description see Reiner et al. (1998).
View Image Figure 21:
Time history of energetic protons and electrons during the period from October 26, 2003 to November 7, 2003. The top panel shows electron data from EPAM/ACE (top trace) and PET/SAMPEX (1.9 to 6.6 MeV). The SAMPEX points are averaged over separate polar passes, including only data obtained at invariant latitudes > 75. It is possible that the intensities shown near the end of 29 October through 30 October (SEP event 3) are overestimated because of background contributions. The middle panel shows low-energy proton data from ACE/EPAM and the bottom panel includes protons measured by GOES-11 in six different energy intervals. The occurrence of X-class flares (obtained from NOAA) are indicated by dotted vertical lines with the intensity labeled above each line. Interplanetary shocks are indicated by dashed vertical lines labeled by an “s”. Major proton events during this interval are labeled 1 to 5. From Mewaldt et al. (2005).
View Image Figure 22:
Time profiles of the strong SEP proton flux event of November 4, 2001. The peak at the time of shock passage is clearly defined early on November 6, even at proton energies as high as 510 – 700 MeV. From Reames (2004).
View Image Figure 23:
Typical intensity-time profiles for protons of 3 different energies are shown as seen by observers viewing a large CME-driven shock from 3 different longitudes indicated. The observer seeing a western event (left hand panel) is well connected to the nose of the shock early and sees rapid rise and decline. Another observer near central meridian (middle panel) is well-connected until the shock passes; thus, he sees flat profiles. The observer viewing an eastern event is poorly connected until after the local shock passes, when he is on the field lines that connect him to the powerful nose of the shock (from behind). From Reames et al. (1996)
View Image Figure 24:
Increase profiles of the GLE observed with 5-min averages by Tsumeb and Moscow neutron monitors. The vertical arrow indicates the start of bright radio emission at 1102 UT. The horizontal bar marks the time when neutrons were detected by the SONG instrument at CORONAS-F spacecraft. From Miroshnichenko et al. (2005).
Watch/download Movie Figure 25: (mpg-Movie; 343 KB)
Movie: The “light bulb” CME, as observed by the LASCO C2 and C3 coronagraphs onboard SOHO. The animation covers a time period of about 24 hours, starting on February 27, 2000, 00:18 UT.
View Image Figure 26:
Examples of CMEs as observed by the LASCO C2 and C3 coronagraphs on SOHO.
Watch/download Movie Figure 27: (mpg-Movie; 4727 KB)
Movie: The limb CME of November 5, 1997, as seen by the LASCO C2 and C3 coronagraphs on SOHO.
Watch/download Movie Figure 28: (mpg-Movie; 1753 KB)
Movie: The balloon type CME of June 21, 1998, as seen by the LASCO C1 coronagraph on SOHO.
Watch/download Movie Figure 29: (mpg-Movie; 1088 KB)
Movie: The limb CME of March 14, 2005, as seen by the LASCO C2 coronagraph
View Image Figure 30:
Left panel: Time-height diagram for the CME of June 2, 1998. Right panel: Time-height diagram for the light bulb CME, as derived by Yashiro et al. (2004), see External Linkhttp://cdaw.gsfc.nasa.gov/CME_list/)
View Image Figure 31:
Examples of halo CMEs as observed by the LASCO C2 and C3 coronagraphs on SOHO.
Watch/download Movie Figure 32: (mpg-Movie; 3798 KB)
Movie: A series of halo CMEs, observed by the LASCO C3 coronagraph on SOHO from January 14 to 18, 2005.
Watch/download Movie Figure 33: (mpg-Movie; 1320 KB)
Movie: The halo CME of November 4, 2001, as seen by the LASCO C3 coronagraph on SOHO. The loudness of the sound represents the intensity of SEPs during the event. This and other sonifications were prepared by a group of talented musician scientist at SSL in Berkeley External Linkhttp://cse.ssl.berkeley.edu/impact/sounds.html
View Image Figure 34:
This shock event was observed by the Helios 1 solar probe during 3 days in 1981, at a distance from the Sun of 0.53 AU and at 92 west of the Earth–Sun line, i.e., right above the Sun’s west limb as seen from the Earth. The panels show the solar wind parameters (from bottom to top): proton density, temperature, flow speed, magnetic field magnitude and its azimuth and elevation angles. The upper panel shows the azimuth flow direction of suprathermal electrons (at 221 eV), the direction away from the Sun being at 180. The jumps in all parameters and the sudden widening of the electron angular distribution at 19:20 UT on day 171 denotes the arrival of a fast shock wave. The time between 02:00 and 19:00 UT (shaded area) on day 172 denotes the passage of a magnetic cloud, with its characteristic change of the field direction in the sense of a magnetic flux rope, and the simultaneous appearance of oppositely flowing (bi-directional) suprathermal electron streams. Note also the mono-directional electron flow before and after the event series. This one of the cases for which Sheeley Jr et al. (1985), using the SOLWIND coronagraph, could observe a uniquely correlated CME. From Schwenn et al. (2005).
View Image Figure 35:
The ICME travel times plotted vs the halo expansion speed Vexp for the 75 usable cases of unique CME-shock correlations. The travel time Ttr is defined by the CME’s first appearance in C2 images and the shock arrival at 1 AU. The solid line is a least square fit curve to the 80 data points, the fit function being Ttr = 20320.77×ln (Vexp). The standard deviation from the fit curve is 14 hours. The two dotted lines denote a 95% certainty margin of two standard deviations. The thin dashed line marks the calculated travel time for a constant radial propagation speed (kinematic approach) inferred from the observed expansion speed according to relation (1). The green dots denote ICMEs without shock signatures, i.e., magnetic clouds (M) and plasma blobs (B). These points were not used for the fit. From Schwenn et al. (2005).