A Skeptic’s View of the CME-Flare Relationship

Russ Howard

NRL

Background

• A very commonly held opinion is that the CME-Flare relationship is now well understood

• We need to be careful how we define a CME and a Flare– A CME is an outwardly moving brightness enhancement seen in a WLC– A flare is a brightening in chromospheric, transition region or coronal lines– Associating lists or rates is very dangerous and mixes apples and oranges

• In this definition, there are many instances of flares without CMEs – the count of CMEs include very small (jet-like) brightness enhancements

• All of the current CME theories have a “flare” as a necessary consequence of the eruption, although perhaps not a cause and effect relationship

• But there are also CMEs without flares– This is often written off as due to occurring on the “backside” or that the

flare is faint and isn’t significant in the GOES 1-8 Angstrom flux.– A class of CMEs have been identified which do not have chromospheric

signatures

“Streamer Blowouts”

• CMEs that occur at an almost constant rate throughout the solar cycle (1 every 5-10 days)

• A process of 1. Small discrete streamer enhancements with a gradual swelling

and expansion of the streamer 2. Followed by a faster eruption3. And then the streamer disappears

CME RATE vs Solar Cycle SB RATE vs Solar Cycle

Example of a Streamer

Blowout CME that occurred on

1 Jun 2008 (Robbrecht et al 2008, in prep)

STEREO-AEUVICOR1COR220085/31-6/2

There is NO Disk Signature

STEREO-B STEREO-A

Summary

• Please let’s not be scientific lemmings