Coronal Hard X-raysCome of Age

H. S. Hudson

SSL, UC Berkeley

St. Andrews Jan. 20, 2009

What are coronal hard X-rays?

• Direct emission from dynamic structures in the corona, rather than Neupert/SHS/footpoint paradigm

• An alternative source of knowledge (viz. radio) on particle distribution functions

• RHESSI (the 4th HXR imager) has shown that one can routinely see coronal hard X-ray emission

St. Andrews Jan. 20, 2009

A deceptive view of flare physics?

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St. Andrews Jan. 20, 2009

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Old

New

Coronal Hard X-rays: Old & New

St. Andrews Jan. 20, 2009

Conclusions

• Krucker et al., A&A Review 2008• All major events show high coronal hard X-ray sources• Emission detected even at energies above 100 keV• Focusing optics holds great promise to extend this

diagnostic tool by orders of magnitude in sensitivity

St. Andrews Jan. 20, 2009

Challenge

• How can we make new progress in high-energy solar physics?

- a RHESSI follow-on

- a Nobeyama follow-on (FASR)