January 30 2006Nobeyama radioheliograph visit Microwave Signatures of Fast CMEs Nat Gopalswamy NASA Goddard Space Flight Center Greenbelt MD 20771 USA

January 30 2006 Nobeyama radioheliograph visit

Microwave Signatures of Fast CMEs

Nat Gopalswamy

NASA Goddard Space Flight Center

Greenbelt MD 20771 USA


Plan of study

• Select all CMEs with speed > 1500 km/s for the period 1996-2005

• Look for eruptive and flare signatures

• If eruptive, compare kinematics from NoRH and LASCO

• Distinguish disk and Limb Signatures

• Make new images if needed


Motivation

• Fast and Wide CMEs important for space weather

• Identifying a microwave signature may be a useful tool to characterize these CMEs


Initial set of fast events (speed V > 1500 km/s) to look for Microwave activity (38 events in Nobeyama Time Window)-----------------------------------CME first appearance V(km/s) Preliminary Survey-----------------------------------1998/03/31 06:12:02.000 19921998/04/23 05:27:07.000 1618 One frame shows eruption 5:46:20 east limb1998/05/09 03:35:58.000 2331 03:36 - 04:26 west limb1998/06/04 02:04:45.000 1802 NW limb NoRH PE at 1:36 (not in catalog), EIT dimming 1:582000/05/12 23:26:05.000 2604 NoRH Data gap?2000/11/08 23:06:05.000 1738 double eruption (GRL), two NORH AFs2000/11/25 01:31:58.000 2519 NE quadrant appearance of an elongated feature before flare 2001/04/03 03:26:05.000 1613 something disappears bet 3:05 &3:25 above AR EIT dim3:052001/04/05 02:06:06.000 1857 (narrow) diffuse behind the limb? Flare in the east2001/04/10 05:30:00.000 2411 disk event2001/04/18 02:30:05.000 2465 well studied.2001/05/30 00:06:07.000 2087 PE (not cataloged) 00:00 to 00:20 east limb2001/06/11 04:54:05.000 1647 (narrow 37 deg) 3:50-4:10 nonradial ejection?2001/08/15 23:54:05.000 1575 backside nothing in NoRH obvious2001/11/25 23:06:54.000 1574 onset before NoRH obs start2002/04/21 01:27:20.000 2393 studied2002/05/22 03:50:05.000 1557 interaction event; cataloged; need shifted HR images2002/05/30 05:06:05.000 1625 EIT at 4:48; 4:55 noRH brightening2002/07/23 00:42:05.000 2285 rhessi HR images available?2002/08/24 01:27:19.000 1913 good event HR images needed2002/09/27 01:54:05.000 1502 SW narrow; eruption at 1:30 SW2002/10/27 23:18:13.000 2115 two events? this CME source is backside? EIT 3042002/11/10 03:30:11.000 1670 ejecta at 3:20 SW2003/01/22 23:54:05.000 1855 (jet) poor images2003/05/31 02:30:19.000 1835 no EIT westward extension 17 GHz at 2:38; changes ~2:20 SW2003/06/02 00:30:07.000 1656 eruption 00:00 to 00:10?2003/06/15 23:54:05.000 2053 change at~23:10 above east limb; elongation of 17 Ghz at 23:562003/06/17 23:18:14.000 1813 flare started before obs. start2003/10/31 04:42:50.000 2126 (narrow) PE 4:40 - 5:00 not cataloged2003/11/09 06:30:05.000 2008 backside east limb2004/01/07 04:06:07.000 1581 PE 4:10-4:40; first brightening at 3:502004/01/08 05:06:05.000 1713 elongated feature disappears near AR after brightening; same AR2004/04/11 04:30:06.000 1645 SW quad 4:00-4:10 ejection2004/11/10 02:26:05.000 3387 NW quad EW arcade2005/01/15 06:30:05.000 2049 NNW quad bright arcade2005/01/15 23:06:50.000 2861 bad images2005/07/27 04:54:05.000 1787 4:30-510 PE not cataloged2005/07/30 06:50:28.000 1968 PE not cataloged?---------------------------------------------------------


Related issues


Extend the PE-CME Relationship to 2005


Low Frequency Type II Bursts, CMEs, and Space Weather

Nat Gopalswamy

NASA Goddard Space Flight Center

Greenbelt MD 20771 USA

Observing metric type II bursts alone is not enough to track CMEs into theHeliosphere


Why Study Low-frequency Type II Bursts?

• Among solar radio bursts, type II bursts are important for space weather because they help remote-sense large-scale mass motion

• Type II bursts at decameter-hectometric (DH) and longer wavelengths are indicative of fast and wide CMEs that are geoeffective & SEPeffective

• SEP events due to CME-driven shocks & geomagnetic storms happen when CMEs impinge on Earth’s magnetosphere

• Type II bursts are also indicative of large-scale interplanetary disturbances that may impact other locations in the heliosphere (e.g. at and enroute to Mars)


Sources of Geoeffective & SEPeffective CMEs

15W

N

S

WE

O Dst < - 200 nTO - 300nT < Dst < - 200 nT

O Dst < - 300 nT

37/55 = 67%18/55 = 33%

SEP

Type II bursts can detect both of these populations


Interplanetary (1973: Malitson et al.)Coronal (1947)

Nelson & Labrum, (1985)

Gap filled by Wind/WAVESAt Decameter-Hectometric (DH)Wavelengths(Bougeret et al. 1995)

Ionospheric Cutoff

1.5 2.5 20Rs 214

Type II, Type III burstsType III storms are observedin the IP mediumSome type IVless complex

SOHO/LASCO FOV2-32 Rs


2005/09/10 22:37 UT CME 1893 km/s PA120• Very intense type II radio bursts: Shock-driving capability of CMEs. • 1-14 MHz crucial because the associated CMEs just leave the Sun• Sky-plane height of the CME is ~9 Ro

8.56 Ro

800 kHz

“The bow shocks of fast, large CMEs are strong interplanetary (IP) shocks, and the associated radio emissions often consist of single broad bands starting below ~4 MHz; such emissions were previously called IP type II events.” Cane & Erickson 2005


IP type II bursts

“The bow shocks of fast, large CMEs are strong interplanetary (IP) shocks, and the associated radio emissions often consist of single broad bands starting below ~4 MHz; such emissions were previously called IP type II events.”

“… metric type II bursts, unlike IP type II events, are not caused by shocks driven in front of CMEs.”

Cane & Erickson 2005


A DH Type II & its CME

f =0 .85MHz fp = 0.425 MHz n = 2.2x103 cm-3 when the CME is at 30 RsVcme ~ 770 km/sRadio emission tracks CME beyond LASCO FOV

2.86 Rs

3.98 Rs 15.58 Rs 22.21Rs

No Type II yet

CME at edge of C3 FOV (30 Rs)

at the edge of C2 FOV

Type II starts


Type II in variousWavelength Ranges

m

DH

kmkm type II

Metric Type II

DH Type II

m-km Type II (m not shown)

DH Type II (no m)

Observed type II features: m – pure metric (ground); DH-decameter-hectometric;km – kilometric; some start at m and go all the way to km (m-to-km)

f

t


Type II Bursts Organized by CMEs

m

DH

km

Speeds, widths & deceleration of CMEs progressively increase for metric, DH, full-range (m-to-km) Type II Bursts, compared

to the general populationPurely km type IIs due to accelerating

CMEs, which form shocks far away from the Sun


Properties of CMEs associated with m, DH and m-to-km type II’s compared to those of all CMEs

CME Property All m DH mkmSEP

km

Speed (km/s) 487 610 1115 14901524

539

Width (deg) 45 96 139 171186

80

Halos (%) 3.3 3.8 45.2 71.472

17.2

Acceleration(m/s2) -2 -3 -7 -11-11

+3

m-to-km (mkm) CMEs similar to SEP-producing CMEs km CMEs similar tometric CMEs, but acceleration is different

m

DH

km


SEP & m-to-km Events


km

Speed (km/s) 487 610 1115 14901524

539

Width (deg) 45 96 139 171186

80

Halos (%) 3.3 3.8 45.2 71.472

17.2


+3


km

Speed (km/s) 487 610 1115 14901524

539

Width (deg) 45 96 139 171186

80

Halos (%) 3.3 3.8 45.2 71.472

17.2


+3

• Similar number of SEP and m-to-km events same shock accelerates electrons and protons

• Difference due to connectivity for particle and wider beam for bursts

• 33.8% of m-to-km events to the east of W10; only 13.8% of SEP events to the east of W10


SEP Release height

Leading edge of the CME at the time of GLE release


Shocks & Type IIs

Close similarity between rates of SEP events, IP type II bursts & in situ shocks

Electron and proton acceleration by the same shock

IP


CMEs Relevant for Space Weather

electronAcceleration(CME shock)

protonAccelerationCME shock

PlasmagImpactCME

CMEs of heliospheric consequences V1000 km/s


Characteristic Speeds

“1980s view” of Alfven speed

Region 1: Difficult to make Type II bursts – explains Type II starting f ~150 MHz

Region 2: Easy to make Type IIs below 2.5 Ro (m)

Region 3: IP medium – VeryFast CMEs & accelerating CMEs produce type II

Krogulec et al 1994Mann et al. 1999Gopalswamy et al. 2001


Occurrence Rates

• 10% of CMEs & 5% of flares have type IIs

• m type IIs most abundant

• m type IIs 2-3 times more abundant than IP type IIs


Starting frequency & CME height

Type II behind CME leading edgeType II & CME in different directionsIP and metric drift rates can be Different if the acceleration Initially occurs in the Qperp region and later (IP) in the Q|| region (Holman & Pesses,1983)


Two possible Type II Locations

• Flanks: Lower Alfven speeds expected. For a given CME speed, there may be a shock at the flanks, while no shock at the nose

• Shock may be Quasiperp at the CME flanks while quasiparallel at the nose

Flank

FlankNOSE


m-to-km Type II bursts and Space Weather

• Less than 1% of the 9000 CMEs observed during 1996-2004 were associated with the m-to-km type II bursts.

• Therefore, the m-to-km bursts can isolate the small fraction of CMEs that are likely to have significant impact on the inner heliosphere

• It takes typically about an hour for the disturbances to reach km level

• Very useful for ESPs and SSCs

• Maybe useful for SEPs


2005 Jan 17 AR 720


Interaction Event

2548 km/s

2094 km/s


Summary

• The speed and width of CMEs progressively increase in the following order: general population, metric-associated, DH-associated m-to-km-associated

• m-to-km CMEs similar to SEP-producing• m-to-km type IIs probe the entire Sun-Earth connected

Space and the energetic CMEs propagating throughout this region.

• They can predict shocks of significance to Earth and other destinations in the heliosphere

• m type IIs alone cannot tell whether the CMEs are geoeffective. They need to have IP counterpart.


Additional Comments• Imaging the type IIs is ideal (SIRA)• Otherwise, at least we need direction finding at

sufficiently high frequencies (above 1 MHz)• The lower sensitivity at higher frequencies is one thing

that needs to be avoided• RPW should be able to measure shock strength when

the shock is still closer to the Sun

Documents

January 30 2006Nobeyama radioheliograph visit Microwave Signatures of Fast CMEs Nat Gopalswamy NASA Goddard Space Flight Center Greenbelt MD 20771 USA