Abstract
Enhanced acceleration of protons to high energy by relatively modest high power ultra-short laser pulses, interacting with snow micro-structured targets was recently proposed. A notably increased proton energy was attributed to a combination of several mechanisms such as localized enhancement of the laser field intensity near the tip of $1~\unicode[STIX]{x03BC}\text{m}$ size whisker and increase in the hot electron concentration near the tip. Moreover, the use of mass-limited target prevents undesirable spread of absorbed laser energy out of the interaction zone. With increasing laser intensity a Coulomb explosion of the positively charged whisker will occur. All these mechanisms are functions of the local density profile and strongly depend on the laser pre-pulse structure. To clarify the effect of the pre-pulse on the state of the snow micro-structured target at the time of interaction with the main pulse, we measured the optical damage threshold (ODT) of the snow targets. ODT of $0.4~\text{J}/\text{cm}^{2}$ was measured by irradiating snow micro-structured targets with 50 fs duration pulses of Ti:Sapphire laser.
Highlights
Over the last two decades a variety of proton acceleration schemes were proposed and demonstrated, such as Target Normal Sheath Acceleration (TNSA)[3,4,5], Radiation Pressure Acceleration (RPA)[6, 7], Break Out Afterburner (BOA)[8, 9] and collisionless shock acceleration[10, 11]
At high laser intensities required for proton acceleration, elimination of pre-plasma requires a ratio between the main pulse to the Correspondence to: O
We report experiments aimed to measure the optical damage threshold (ODT) and energy deposition in snow targets irradiated by a short pulse intense laser
Summary
Over the last two decades a variety of proton acceleration schemes were proposed and demonstrated (see Refs. [1, 2] for review), such as Target Normal Sheath Acceleration (TNSA)[3,4,5], Radiation Pressure Acceleration (RPA)[6, 7], Break Out Afterburner (BOA)[8, 9] and collisionless shock acceleration[10, 11]. A recent review on ‘targetry’ for application of laser–proton acceleration to cancer radiotherapy is reported in reference[19] These schemes require laser pulses exceeding 1 PW level on the target in order to accelerate protons to energies of about 150 MeV and are optimized for interaction of the main pulse with cold solid matter. In high power systems that include a regenerative amplifier, the energy leakage during amplification in regenerative amplifier (prepulse), is strongly focused on the target and can reach laser intensities of 1012 W/cm. In high power systems that include a regenerative amplifier, the energy leakage during amplification in regenerative amplifier (prepulse), is strongly focused on the target and can reach laser intensities of 1012 W/cm2 At these intensities, the laser pulse is strongly interacting with the target. At high laser intensities required for proton acceleration, elimination of pre-plasma requires a ratio between the main pulse to the
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
