Estimation of output gap and investigate impactful factors on it in the economy of Afghanistan (2008-2017)

The output gap reflects the economy performance of a country, thereby increase or decrease leads to inflation or stagnation. Production output gap can determine the direction of economic policy for growth of countries. The purpose of this study is to estimate the output gap and to investigate the impact of real exchange rate, export and import on it in Afghanistan during the years (2008-2017). The Hodrick-Prescott model is used to estimate the output gap and Vector auto regression (VAR) model is used to investigate the impact of 3 variables (real exchange rate, export, and import) on dependent variable (output gap). The data applied in this study was seasonal. Results show that Gross Domestic Product (GDP) had fluctuation during (2008-2017), relatedly real exchange rate had a positive effect, export and import had negative effects on the output gap. According to variance analysis, the real exchange rate had the highest effect and import had the lowest effect. At the end, based on the variance analysis results, the instant functions show that incoming momentum of output gap and exchange rate will cause strong fluctuations in Gross Domestic Product (GDP) trend, relatedly export and import cause weak fluctuation.

Field structure and electron acceleration in a slit laser beam

The electric field intensity distribution and the phase velocity distribution of a slit in laser beams with different parameters are analyzed. Using three-dimensional test particle simulation, the laser beam with a slit induced acceleration of electrons with different initial momenta is investigated. Contrary to anticipation, the maximum net energy gain is not monotone increasing as the incoming momentum increasing. Based on the field structure and analysis, we gave an explanation for this.