Interplanetary Type IV Bursts

Abstract

We study the characteristics of moving type IV radio bursts that extend to hectometric wavelengths (interplanetary type IV or type $\text{IV}_{\text{IP}}$ bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48 interplanetary type IV bursts observed with the Radio and Plasma Wave Investigation (WAVES) instrument onboard Wind in the 13.825 MHz – 20 kHz frequency range. The dynamic spectra of the Radio Solar Telescope Network (RSTN), the Nançay Decametric Array (DAM), the Appareil de Routine pour le Traitement et l’ Enregistrement Magnetique de l’ Information Spectral (ARTEMIS-IV), the Culgoora, Hiraso, and the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN) Radio Spectrographs were used to track the evolution of the events in the low corona. These were supplemented with soft X-ray (SXR) flux-measurements from the Geostationary Operational Environmental Satellite (GOES) and coronal mass ejections (CME) data from the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). Positional information of the coronal bursts was obtained by the Nançay Radioheliograph (NRH). We examined the relationship of the type IV events with coronal radio bursts, CMEs, and SXR flares. The majority of the events (45) were characterized as compact, their duration was on average 106 minutes. This type of events was, mostly, associated with M- and X-class flares (40 out of 45) and fast CMEs, 32 of these events had CMEs faster than $1000~\mbox{km}\,\mbox{s}^{-1}$. Furthermore, in 43 compact events the CME was possibly subjected to reduced aerodynamic drag as it was propagating in the wake of a previous CME. A minority (three) of long-lived type $\text{IV}_{\text{IP}}$ bursts was detected, with durations from 960 minutes to 115 hours. These events are referred to as extended or long duration and appear to replenish their energetic electron content, possibly from electrons escaping from the corresponding coronal type IV bursts. The latter were found to persist on the disk, for tens of hours to days. Prominent among them was the unusual interplanetary type IV burst of 18 – 23 May 2002, which is the longest event in the Wind/WAVES catalog. The three extended events were typically accompanied by a number of flares, of GOES class C in their majority, and of CMEs, many of which were slow and narrow.

Appendix: Comprehensive Catalog of the Type \(\text{IV}_{\text{IP}}\) Burst Records

In Table 1, which is attached as online supplementary material, we provide a summary of the interplanetary type IV bursts recorded by the Wind/WAVES R1 and R2 receivers in the 13.825 MHz – 20 kHz frequency range, with their associated CMEs and SXR flares in the 1998 – 2012 period. The coronal extensions of these bursts by the RSTN, DAM, ARTEMIS-IV, Culgoora, Hiraiso, and IZMIRAN Radio Spectrographs are included for comparison.

The headline to each event includes the event number, date of observation, and characterization of the event as compact or extended following the classification introduced in Section 3. Column 1 lists the type of activity; for SXR flares we list the GOES class. The secondary headline, CME preceding main ejection, stands for CMEs preceding the main CME associated with the event by approximately two days along the same path. The path similarity is determined by the comparison of the position angle (PA) and width of the preceding CME to the main. In the extended events, the secondary headline is sometimes absent as they may originate from a number of energetic events (flares and CMEs) and not from a powerful flare or fast CME with the latter propagating in the wake of preceding ejections (see discussion in Section 5). Columns 2 – 3 list start, peak, and end of each type of activity in day, month, hour, and minute (DD MMM HH:MM) format. D indicates that the event extends in time beyond the observation period. The CME start time, in the second column, is the first C2 appearance, while its extrapolated lift-off time appears in the next row as a remark (see below for the description of the remark lines). In the fourth column, we list the SXR flare 1 – 8 Å integrated flux ($\text{F}^{\mathrm{tot}}_{\text{SXR}}$ in $\mbox{J}\,\mbox{m}^{-2}$), and in the same column, the CME speed ($\text{V}_{\text{CME}}$) in $\mbox{km}\,\mbox{s}^{-1}$. The location of the flare on the disk and the measured position angle (MPA) of the CMEs with their angular widths in parenthesis are given in the fifth column. The SXR flare location is determined from the position of the associated $\mathrm{H}\alpha$ flare on the disk or the Solar X-ray Imager of GOES report if available. In the fifth column, we also report the position of the coronal radio bursts when NRH records are available. In the sixth column we list the frequency range of the radio bursts in MHz; L indicates that the burst extends to lower frequencies, H stands for a high-frequency extension.

Comments and remarks, when necessary, are in separate lines below the description of the activity line. The comments include the reporting stations from which the data of each observation were obtained, together with the classification of the Wind/WAVES, the SOHO/LASCO records, and the NOAA active region number of the event. For the flares, the SXR peak and the $\mathrm{H}\alpha$ category when available are reported, while for the CMEs the extrapolated lift-off time is presented. Finally, in the comment lines data gaps are reported (if any).

The reporting observatory or space experiment abbreviations used in Table 1 are as follows:

• ART-4 ARTEMIS-IV, Greece

• CUL Culgoora, Australia

• SAG RSTN, Sagamore Hill, Massachusetts, USA

• PAL RSTN, Palehua, Hawaii

• HOL RSTN, Holloman, New Mexico, USA

• LEA RSTN, Learmonth, Australia

• SVI RSTN, San Vito, Italy

• RAM Ramey AFB, Puerto Rico, USA

• IZM IZMIRAN Radio Spectrograph

• KANZ Kanzelhöhe Solar Observatory

• MIT National Astronomical Observatory of Japan, Mitaka

• HiRAS Hiraiso Radio Spectrograph

• DAM Nançay Decameter Array

• NRH Nançay Radioheliograph

• XFL SXR flare from the GOES Solar X-ray Imager (SXI)

• Gxx SXR flare from the GOES (for example G08 stands for GOES 08)

All abbreviations, with the exception of NRH, DAM, and ART-4, are adopted from the Space Weather Prediction Center¹¹ station list.