Science case a): Using the strongest lines present in the EIS spectrum, we look for fast magnetoacoustic waves in active region loops. We use a small number of lines to try and keep the cadence of the observations as low as possible. We note, for example, that Roberts et al. (1984) predict the fast sausage wave to have a period of the order of one second. We shall find out the signature of different modes of the fast acoustic oscillations, i.e., kink and sausage modes of the oscillations. The measurements of oscillation period and other observational parameters, along with basic flux tube MHD theory and coronal seismology, will allow us the more sophisticated easurements of the magnetic field in solar atmosphere with Hinode. We attempt here to find these fast oscillations using EIS and as a test of the EIS temporal resolution.The additional observations with very hot flare lines will also explore the hot loop oscillations and give a chance to study its possible drivers. We use the 40" slot so as to obtain images of the active region loops. We will look for material flows/waves in these loops at speeds appropriate to those of fast MHD waves, e.g., using difference images. Science case: Here we will measure densities in the active region loops in the form of time series obtained with the 40" slot. These densities are necessary in order to enable us to obtain estimates of magnetic field strength in the magnetic loops, using the periods of oscillation previously measured from the arm_fastslot_waves study. These observations are also interesting as a test of the different density diagnostic present in the EIS spectrum. We will test three different diagnostics here, Fe XII 186.9/195.1, Fe XIII 203.8/202.0 and Fe XIII 196.54/202/04. We are also interested in finding locations in the active region loops where there are localised density increases which may be indicators of magnetic reconnection. Science case b): Here we will measure densities in the active region loops in the form of time series obtained with the 40" slot. These densities are necessary in order to enable us to obtain estimates of magnetic field strength in the magnetic loops, using the periods of oscillation previously measured from the arm_fastslot_waves study. |
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