en اندرکنش نور با ماده Interaction of Light and Matter پژوهشي Research <span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">This paper investigates the phenomena of Normalized intensity of laser field (NILF) and self-focusing in a collisionless underdense plasma using Hermite-Gaussian laser pulse. NILF is an effective method to generate stronger self-focusing and high self-focusing length. This study focuses on the utilization of Hermite-Gaussian laser pulse to investigate NILF and self-focusing effectively. The influences of different hermite mode index value and initial amplitude of electric field of Hermite-Gaussian are examined on NILF and self-focusing. NILF has been plotted against propagation distance in plasma. Our research reveals that the NILF grows as the Hermite mode index value increases, regardless of the initial amplitude of Hermite-Gaussian electric field. Under different conditions, we observe that NILF also increases with the initial amplitude of Hermite-Gaussian electric field increases, when the Hermite mode index value is fixed. As a result, the self-focusing becomes stronger as the NILF increases, leading to a longer self-focusing length and an earlier onset of self-focusing. </span></span> Hermite-Gaussian laser pulse, laser intensity, NILF, plasma frequency, Self-focusing 243 254 http://ijop.ir/browse.php?a_code=A-10-995-1&slc_lang=en&sid=1 Mostafa Sadeghzadeh m.sadeghzadeh2012@gmail.com 10031947532846005490 10031947532846005490 Yes Department of Physics, University of Bu-Ali Sina, Hamedan, Iran. Davood Raoufi d_raoufi@yahoo.com 10031947532846005491 10031947532846005491 No Department of Physics, University of Bu-Ali Sina, Hamedan, Iran.