sending object as parameter to ajax and getting in php

Question

In my form, there is a textarea field with ckeditor and file upload option.

<script>
        $("form[name='product_portfolio_edit']").submit(function(e) {
            e.preventDefault(); 
            var name="hh";
            var file_data =jQuery('#product_portfolio_image').prop('files');
             console.log(file_data);
            var desc = CKEDITOR.instances['product_portfolio_description'].getData();
            url="ajax/ajax_productportfolioedit.php";
            $.ajax({
                url: url,
                method: "POST",
                data:{name:name,desc:desc,file_data:file_data},
                success: function (msg) {             
                    msg=msg.trim();
                    if(msg=="Success")
                    {  
                        location.reload();
                    }
                    else
                    {
                        alert("Failed to update");

                    }
                },
                });
            });
  </script>

how to pass file_data in php file.