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We present high spatial resolution observations of chromospheric evaporationin the flare SOL2014-03-29T17:48. Interface Region Imaging Spectrograph (IRIS)observations of the FeXXI 1354.1 A line indicate evaporating plasma at atemperature of 10 MK along the flare ribbon during the flare peak and severalminutes into the decay phase with upflow velocities between 30 km s$^{-1}$ and200 km s$^{-1}$. Hard X-ray (HXR) footpoints were observed by RHESSI for twominutes during the peak of the flare. Their locations coincided with thelocations of the upflows in parts of the southern flare ribbon but the HXRfootpoint source preceded the observation of upflows in FeXXI by 30-75 seconds.However, in other parts of the southern ribbon and in the northern ribbon theobserved upflows were not coincident with a HXR source in time nor space, mostprominently during the decay phase. In this case evaporation is likely causedby energy input via a conductive flux that is established between the hot (25MK) coronal source, which is present during the whole observed time-interval,and the chromosphere. The presented observations suggest that conduction maydrive evaporation not only during the decay phase but also during the flarepeak. Electron beam heating may only play a role in driving evaporation duringthe initial phases of the flare.

How important are electron beams in driving chromospheric evaporation in the 2014 March 29 flare?