A 2.5-dimensional magnetohydrodynamic (MHD) simulation is conducted in a chromosphere-transition-corona setup. The initial arcade-like linear force-free magnetic field is driven by an imposed slow motion converging towards the magnetic inversion line at the bottom boundary, which leads to the formation of a magnetic flux rope (MFR) by magnetic reconnection and eventually to the eruption of a coronal mass ejection (CME). An embedded prominence also gets formed by levitation of chromospheric material. The MFR goes through the initiation phase to the acceleration phase. The reconnection mechanism in the current sheet (CS) underneath the MFR changes from the Sweet-Parker to the unsteady bursty regime of reconnection when the phase transition occurs. We then conduct forward modeling analysis based on MHD simulation of MFR eruption. The CS evolution during MFR eruption can be divided into four stages. The first stage shows the CS to form and gradually lengthen. Resistive instabilities that disrupt the CS mark the beginning of the second stage. Magnetic islands disappear in the third stage, and reappear in the fourth stage. Synthetic images and light curves of the seven SDO/AIA channels, i.e., 94 Å, 131 Å, 171 Å, 193 Å, 211 Å, 304 Å, and 335 Å, and the 3-25 keV thermal X-ray are obtained with forward modeling analysis. The loop-top source and the coronal sources of the soft X-ray are reproduced. Quasi-periodic pulsations (QPPs) appear in some SDO/AIA channels during the periods of intense activities of the magnetic islands.
