Unable to use multiple buckets at same time

Hi I am trying to call the top_hottt function with multiple compatible buckets to be filled but somehow the url gets updated and it takes in the last bucket only. I would want something where i can have multiple values of the bucket. Below is the small snippet of code of how i am trying to achieve the same. I am using .net platform

var parameters = {
"api_key": "12345678", "results": "2", "start": "0", "bucket": "id:7digital-US", "bucket": "familiarity",
"bucket": "hotttnesss", "bucket": "images", "format": "jsonp" };

$.ajax({
    crossDomain: true,
    dataType: 'jsonp',
    jsonpCallback: "topArtist",
    url: "http://developer.echonest.com/api/v4/artist/top_hottt",
    data: parameters,
    success: function (callback) {
        getArtists(callback.response.artists);
    },
    error: function (error) {
        console.log(error);
        console.log("error");
    }
});