[1] This first paper in a two part series summarizes the current theory and the data-driven solar wind model for simulating dynamic spectra of type II radio bursts. It also introduces performance metrics and techniques for extraction of model shock parameters from these dynamic spectra. We use an iterative downhill simplex method which compares two dynamic spectra and quantitatively assesses and improves the agreement using two figures of merit: the first is based on the correlation function and the second is based on a normalized differences over the data set. By maximizing the agreement we are able to extract the input model shock parameters to within 30% or better when using model solar winds of increasing complexity. The effects on the spectra predicted and on the figures of merit from changing the model shock parameters and solar wind model are also investigated. The iterative downhill extraction method is then applied to the type II dynamic spectrum predicted using a realistic model solar wind and a shock model estimated for an observed type II event. The shock parameters are recovered to within 10% of the correct solution.Citation: Hillan, D. S., I. H. Cairns, and P. A. Robinson (2012), Type II solar radio bursts: Modeling and extraction of shock parameters,

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[1] We investigate and predict the observed background levels for the TNR, RAD1, and RAD2 receivers when connected to the X, Y, and Z antennas of the WAVES instrument on the spacecraft Wind. The receivers are connected to either a single antenna, in "SEP" mode, or a combination of antennas, in "SUM" mode. With the TNR receiver in SEP (X) mode, the predicted backgrounds agree to within 20% when modeled using a two component model for the quasi-thermal plasma noise (QTN). Calibrating the RAD1 in SEP (X) mode observations against TNR allows us to calculate the relative receiver gain G R1 = 1.43 ± 0.18. Using the RAD1 data in SUM (X+Z) mode, the ratio of antenna gains is found to be R = 6.5, in agreement with preflight measurements. Observed differences between the SEP (X) and SUM (X+Z) modes are explained for the first time, and the predicted levels of QTN and galactic background are found to agree to within 20%. RAD2 is also calibrated against RAD1 and TNR, yielding a total gain G R2 G y = 2.5 ± 0.3. Differences between the predicted and observed galactic background spectra are used to estimate the effective antenna lengths for the X and Y antennas, which are found to be between the physical monopole antenna length L and the Hansen (1981) prediction of ffiffiffiffiffiffiffiffiffiffiffi ð2=3Þ p L. The analyses are consistent with the Novaco and Brown (1978) galactic background model, which decreases much faster than that of Cane (1979). Our model background spectrum is useful for theory-data comparisons of type II and III bursts.

[1] In this paper, the second in a two paper series, we quantitatively compare a detailed theory for type II solar radio bursts with observations and extract the parameters of the associated shocks. We use the techniques and assessment parameters developed and demonstrated in the companion paper for artificial data sets and solar wind models. Here we investigate three relatively well-observed type II events with estimates of shock parameters from LASCO/SOHO observations of coronal mass ejections (CMEs) or other data. Using these parameters we obtain reasonable qualitative and semiquantitative agreement (25-40% correlations) between the theory and observed dynamic spectra. Then, using an iterative downhill simplex method with two assessment parameters, we extract model shock parameters that increase the agreement between theory and observation in terms of relative flux levels, spectral intensifications and drift rates. The extracted parameters agree qualitatively and semiquantitatively with the parameters (speed, size and expansion index) estimated from CME observations for one of the studied events. The extracted parameters agree qualitatively with the remaining two events and yield new initial shock speeds. The agreement between this multiprocess theory and observations is promising for these first quantitative comparisons performed here. Quantitatively, the bulk of the radio emission agrees to within 5 to 10 dB with observations, with the theory typically overpredicting the intensity of bright spots in the dynamic spectra. The methods and analyses presented here show potential for the remote inference of CME-driven shock parameters and the prediction of radio and space weather events.