## 1 Introduction  
In supersonic flow, various types of shock waves are generated depending on the shape of objects that are involved. Research on the shock-shock intersection and shock reflection on a wall has been conducted for many years. Mach reflection and regular reflection can occur at the same freestream Mach number in some supersonic regions [1; 2], which are called the dual solution domain. Transitions between regular reflection and Mach reflections were also observed in experimental and numerical studies that were performed in this region. However, the mechanism has not been clearly identified. [PERSON] et al. [3] and [PERSON] et al. [4] postulated that the structure of the reflected shock that is generated in the dual solution domain has a hysteresis effect that is influenced by the shape of the shock wave that is generated before it enters the dual solution domain. They also reported that the three-dimensional effect could promote the hysteresis effect. Various methods have been proposed to avoid unfavorable shock structures and to derive advantageous conditions. The shock structure that is generated around a supersonic vehicle and its strength have a great influence on the performance. In early research, there was an attempt to change the shape of a shock wave by attaching an aerospike structure to the forebody. However, such physical structures have problems such as excessive heat load at the end, additional load at the off-design point, and rotational force when maneuvering. Since then, methods for reducing the load of the object without a physical structure have been proposed, such as the gas-injection technique. However, the equipment size that is required is not affordable for flight, so a technique has been proposed using energy that could be used independently for the operating conditions. Electromagnetic waves, microwaves, and laser energy are considered possible sources of energy deposition. [PERSON] et al. [5] investigated the effect of reducing drag by deposition slit-shapedmicrowaves in front of cone-shaped objects. [PERSON] et al. [6] and [PERSON] et al. [7] performed similar studies using a hemispherical model to investigate the effect of the repetition rate on the drag reduction. Recently, [PERSON] et al. [8] performed an experiment using a femtosecond Laser. [PERSON] et al. [9; 10; 11] and [PERSON] et al. [12] deposited laser energy at an intake system and examined the effects on the flow control and performance. Based on a similar principle, the transition from Mach reflection to regular reflection can benefit the performance of high-speed vehicles. Many studies on Mach reflections and regular reflections in supersonic flows have been conducted for this purpose, which can be useful for improving the performance of a supersonic intake. However, few studies have made realistic models or structures to control or generate favorable operating conditions in the supersonic region, although the transition between regular reflection and Mach reflections has been confirmed by many experiments and numerical simulations [13; 14; 15; 16; 17; 18; 19]. The aim of this study is to use laser energy deposition to observe the possibility of transitions from Mach reflection to regular reflection in the dual solution region occurring. The results could be used to improve the performance of high-speed vehicles. For this purpose, shock waves were generated using two symmetrical wedges with the same angle, and laser energy was deposited in the freestream region near the shock wave as a disturbance source. It is reasonable to focus the energy in the freestream region in front of the shock wave to consider a more realistic operating environment. Energy deposition in the area between the shock waves and the wedge surface is less practical because the area can be too small for certain conditions to focus the laser energy. Furthermore, additional factors such as the refraction of the laser beam should be considered.