The Space Weather Week
Monique Pick
LESIA, Observatoire de Paris
13-17 November 2006
Interest of radio observations for CMEs– More particularly forcast those reaching the
Earth– Proxies (Halo)– Future plans
Web site (http://secchirh.obspm.fr)– More particularly forcast those reaching the
Earth– iesFuture plans
Ne (cm-3) fp
low corona 108 100 MHz
~ 10 R ~ 104 ~ 1 MHz
~ 30 R ~ 1.5 103 ~ 350 kHz
~ 1 AU ~ 10 ~ 30 kHz
Radio emissions from the corona and
inner heliosphere
JLB / 2002.04.24 / ST-21 / EGS-Nice - 3 -
Coronal Mass Ejections
Fast and narrow CMES associated with short duration emissions(electron beams, typeIII).
Fast and large CMEs associated withcomplex radio emissions at meterwavelengths lasting >> 10 minutes.Also associated with flares
Radio detects these events above the solar limb and on-disk
Radio complex eventsover a large frequency rangeSimilarity 1MHz and 1-3 GHz Reiner et al. (2001,02)
Long duration >20 min
Origin in low corona
Flare/CME events
CME and Complex radio events
26 complex radio events 20 events associated with shocks (type II-like features)
26 associated with CMEs (also Cane, 2002); 17 halo CMEs; 7 Width> 100°. (reach Earth)
*Emitting radio sources (NRH meter λ) complex and spread over a large volume; onset of new sources
* Coronal processes, involving multiple B system participate in the eruption.
Maia and Pick, ApJ, 609, 1082 2004Pick et al, AdSR 35 1976 2005
Halo CME May 02 1998: Disk observations
Pohjolainen et al., 2001
October 28 2003 Halo CME CME
RH Nançay C2 LASCO
Radio imaging at 164 Mhz
• traces the early CME development and the regions of B interaction• The coronal wave and the CME encompasses most of the solar disk (10 min)
October 28 2003Halpha Moreton wave
Moreton waves
Fast progression in latitudeFull extend: < 10 minSuccessive loop interactionsSuper-alfvenic disturbance
CME proxies
Angular extend Speed (3000km/s)
On-disk and limb CMEs
E
W
N
S
Duration (lateral spread)Indication on V
A new web site for radio monitoring A. Bouteille, R. Romagnan
M. Pick, M. Maksimovic, J. L. Bougeret, A. Lecacheux,(LESIA)
C. Alissandrakis, X. Moussas , A. Hillaris (Greece)A. Vourlidas, R. Howard (NRL) CMEs (V, W, PA)
Goal: one radio spectrum in combining data from different spectrographs (large freq. Range)
-Nançay Radioheliograph (metric λ)
- SECCHI CME summary (in near future)
-Real time
-NRH imaging link with the SWB, Royal Observatory
http://secchirh.obspm.fr/
++
Pair of long duration radio emissions
Post eruptive emissions of long duration dm-dam λ (NRH site) km bandwidth 300kHz drifting, Widely ≠ frequency range.Similar temporal, spectral profiles
Slow drifting BW 300KHz
PFFS extrapolation
Pairs of two continua not connected
If first harmonic emission, velocity of expansion 485 km/s and mean altitude of 5Rs near onset; CME has reached altitude of 6Rs (fp×r = 20kHz 1AU);13 UT 15 Rs
If plasma emission, kilometric source lower density than the source of metric continuum
Suggestion: Destabilization of loop system (Km) created by B interaction between expanding CME and neighbouring loops
Electrons radiating low freq continuum originatesin region of interaction (sporadic m activity)
+
Low frequency continuum
Concluding remarks
• Proxies – improve the characteristics : V , lateral expansion
(statistical study)– Investigation on polarization
• Futur work– S-Waves (STEREO)– Link with other sites– Survey SOHO 1997-to-day, in progress – Spectograph page > 16 hours– Includes spectral frequency range toward microwave
• End
Limb events
Angular development < 10 min
•Electrons trace the expansion of the arch system(~2500 km/sec)•Coronal wave develops along flank of CME In lateral expansion
164 MHz
in IP space
f ≈ R-1
fp = 9 √ Ne
kHz cm-3
Radio emissions from the inner
heliosphere
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