Energetic Particle Experiment ERNE

Torsti, J.; Валтонен, Э.; Lumme, M.; Peltonen, P.; Eronen, T.; Louhola, M.; Riihonen, E.; Schultz, G.; Teittinen, M.; Ahola, Kimmo; Holmlund, Christer; Kelhä, Väinö; Leppälä, Kari; Ruuska, Pekka; Strömmer, Esko

doi:10.1007/978-94-009-0191-9_14

Cited by 45 publications

(30 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The associated RQ CME has a speed of 1020 km/s and a width of 96 • . Figure 7 shows the SEP intensity as observed by SOHO's Energetic and Relativistic Nuclei and Electron (ERNE) experiment (Torsti et al, 1995) in five energy channels along with the GOES soft X-ray light curve. The X1.5 flare associated with the SEP event was quite impulsive.…”

Section: Rq Cmes With Small Sep Eventsmentioning

confidence: 99%

Coronal mass ejections, type II radio bursts, and solar energetic particle events in the SOHO era

et al. 2008

View full text Add to dashboard Cite

Abstract.Using the extensive and uniform data on coronal mass ejections (CMEs), solar energetic particle (SEP) events, and type II radio bursts during the SOHO era, we discuss how the CME properties such as speed, width and solar-source longitude decide whether CMEs are associated with type II radio bursts and SEP events. We discuss why some radio-quiet CMEs are associated with small SEP events while some radio-loud CMEs are not associated with SEP events. We conclude that either some fast and wide CMEs do not drive shocks or they drive weak shocks that do not produce significant levels of particle acceleration. We also infer that the Alfvén speed in the corona and near-Sun interplanetary medium ranges from <200 km/s to ∼1600 km/s. Radio-quiet fast and wide CMEs are also poor SEP producers and the association rate of type II bursts and SEP events steadily increases with CME speed and width (i.e. energy). If we consider western hemispheric CMEs, the SEP association rate increases linearly from ∼30% for 800 km/s CMEs to 100% for ≥1800 km/s. Essentially all type II bursts in the decametre-hectometric (DH) wavelength range are associated with SEP events once the source location on the Sun is taken into account. This is a significant result for space weather applications, because if a CME originating from the western hemisphere is accompanied by a DH type II burst, there is a high probability that it will produce an SEP event.

show abstract

Section: Rq Cmes With Small Sep Eventsmentioning

confidence: 99%

Coronal mass ejections, type II radio bursts, and solar energetic particle events in the SOHO era

et al. 2008

View full text Add to dashboard Cite

show abstract

“…For the ESP observations, 1-min SOHO/ERNE (Torsti et al, 1995) data were used. During the study period, there were some notable data gaps, and some of the very large particle events of the solar cycle 23 had corrupted data.…”

Section: Energetic Particlesmentioning

confidence: 99%

Interplanetary fast forward shocks and energetic storm particle events above 1.5 MeV

Huttunen‐Heikinmaa

Валтонен

2009

Ann. Geophys.

Self Cite

View full text Add to dashboard Cite

Abstract. Interplanetary (IP) shock passages are usually identified by abrupt changes in the plasma parameters, but sometimes they are also associated with energetic storm particles (ESPs). The maximum observed energies of ESPs usually reach a few MeVs per nucleon and occasionally even a few hundred MeVs per nucleon. We have carried out a statistical study of ESP events observed by SOHO/ERNE above 1.5 MeV during the seven-year period between May 1996 and April 2003. In the first stage, we gathered a comprehensive database of IP shock candidates using several readymade shock lists. We defined a qualitative classification for the ESP signals and studied their association with fast forward shocks. We present a survey of the overall statistics of ESP associations with fast forward shocks and the yearly amount of the shocks and associated ESP events during the 7-year study period. Our most important findings are that only 40% of the observed interplanetary fast forward shocks accelerate ESPs to energies greater than 1.5 MeV and that the high-energy ESP-effectiveness of the fast forward shocks has a solar cycle dependence. The yearly ESP-effectiveness varied from 11%, in May 1996-April 1997 (∼activity minimum), to 53% in May 2000-April 2001 (∼activity maximum). We also performed a quantitative analysis of the proton power law spectra at the time of the shock passage. We found that the average spectral index of ESPs was −3.6 with the standard deviation of the distribution of 1.3. The ESP events had significantly larger power law factors than the reference spectra, calculated every day at a certain time for comparison.

show abstract

“…The energy range of protons for Low Energy Detector (LED) is 1.6±13 MeV and for High Energy Detector (HED) 12±100 MeV. A complete description of ERNE is given by Torsti et al (1995).…”

Section: The Instrumentmentioning

confidence: 99%

ERNE observations of energetic particles associated with Earth-directed coronal mass ejections in April and May, 1997

Anttila

Sahla

2000

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Two Earth-directed coronal mass ejections (CMEs), which were most e ective in energetic ($1± 50 MeV) particle acceleration during the ®rst 18 months since the Solar and Heliospheric Observatory (SOHO) launch, occurred on April 7 and May 12, 1997. In the analysis of these events we have deconvoluted the injection spectrum of energetic protons by using the method described by Anttila et al. In order to apply the method developed earlier for data of a rotating satellite (Geostationary Operational Environmental Satellites, GOES), we ®rst had to develop a method to calculate the omnidirectional energetic particle intensities from the observations of Energetic and Relativistic Nuclei and Electrons (ERNE), which is an energetic particle detector onboard the three-axis stabilized SOHO spacecraft. The omnidirectional intensities are calculated by ®tting an exponential pitch angle distribution from directional information of energetic protons observed by ERNE. The results of the analysis show that, compared to a much faster and more intensive CMEs observed during the previous solar maximum, the acceleration e ciency decreases fast when the shock propagates outward from the Sun. The particles injected at distances <0.5 AU from the Sun dominate the particle¯ux during the whole period, when the shock propagates to the site of the spacecraft. The main portion of particles injected by the shock during its propagation further outward from the Sun are trapped around the shock, and are seen as an intensity increase at the time of the shock passage.

show abstract

Energetic Particle Experiment ERNE

Cited by 45 publications

References 6 publications

Coronal mass ejections, type II radio bursts, and solar energetic particle events in the SOHO era

Coronal mass ejections, type II radio bursts, and solar energetic particle events in the SOHO era

Interplanetary fast forward shocks and energetic storm particle events above 1.5 MeV

ERNE observations of energetic particles associated with Earth-directed coronal mass ejections in April and May, 1997

Contact Info

Product

Resources

About